Questions

2 Marks Questions

Take a timed test

62 questions · self-marked practice — reveal the answer and mark yourself.

Question 12 Marks
In figure 3.80, if PQ = 6, QR = 10, PS = 8 find TS.
Answer
Given: PQ = 6, QR = 10, PS = 8
PT × PS = PR × PQ
This property is known as theorem of chords intersecting outside the circle.
⇒ PR = PQ + RQ = 6 + 10 = 16
⇒ PT × 8 = 16 × 6
⇒ PT = 12
TS = PT – PS = 12 – 8 = 4
View full question & answer
Question 22 Marks
In figure 3.78, chord MN and chord RS intersect at point D.
(1) If RD = 15, DS = 4, MD = 8 find DN
(2) If RS = 18, MD = 9, DN = 8 find DS
Answer
Given RD = 15, DS = 4, MD = 8
MD × DN = RD × DS
This property is known as theorem of chords intersecting inside the circle.
⇒ 8 × DN = 15 × 4
$\Rightarrow DN = \frac{15}{2} = 7.5$
(2)Given RS = 18, MD = 9, DN = 8
Here, RS = 18
Let RD = x and DS = 18 – x
MD × DN = RD × DS
This property is known as theorem of chords intersecting inside the circle.
$\Rightarrow 8 \times 9=x \times(18-x)$
$\Rightarrow 18 x-x^2=72$
$\Rightarrow x^2-18 x+72=0$
$\Rightarrow(x-12)(x-6)=0$
$\Rightarrow x=12 \text { or } 6$
$\Rightarrow D S=6 \text { or } 12$
View full question & answer
Question 32 Marks
In figure 3.77, ray PQ touches the circle at point Q. PQ = 12, PR = 8, find PS and RS.
Answer
$\text { Given } P Q=12, P R=8$
$S P \times R P=P Q^2$
This property is known as tangent secant segments theorem.
$\Rightarrow P S \times 8=12^2$
$\Rightarrow PS = \frac{144}{8}= 18$
RS = PS – RP = 18 – 8 = 10
View full question & answer
Question 42 Marks
In figure 3.61, chords AC and DE intersect at B. If ∠ ABE = 108°, m(arc AE) = 95°, find m(arc DC).
Answer
Given ∠ ABE = 108°, m(arc AE) = 95°
Using the property of the secant,
$\angle A B E=\frac{1}{2}[m(\operatorname{arc} A E)+m(\operatorname{arc} D C)] $
$ \Rightarrow 108^{\circ}=\frac{1}{2}\left[95^{\circ}+m(\operatorname{arc} D C)\right]$
⇒m(arc DC) = 108° × 2 – 95°
⇒m(arc DC) = 121°
View full question & answer
Question 52 Marks
In figure 3.60, m(arc NS) = 125°, m(arc EF) = 37°, find the measure ∠ NMS.
Answer
Given m(arc NS) = 125°, m(arc EF) = 37°
Also, ∠ NMS is an external angle, so
$\angle N M S=\frac{1}{2}[m(\operatorname{arcNS})-m(\operatorname{arcEF})] $
$ \Rightarrow \angle N M S=\frac{1}{2}\left[125^{\circ}-37^{\circ}\right]$
$ \Rightarrow \angle N M S=\frac{1}{2} \times 88^{\circ}=44^{\circ}$
View full question & answer
Question 62 Marks
In figure 3.59, altitudes YZ and XT of
∆ WXY intersect at P. Prove that,

(1) $\square$WZPT is cyclic.
(2) Points X, Z, T, Y are concyclic.
Answer
In WZPT,
∠ WZP = ∠ WTP = 90° {YZ and XT are the altitudes}
If a pair of opposite angles of a quadrilateral is supplementary, then the
quadrilateral is cyclic.
⇒ WZPT is cyclic.
(2)∵ X, Z,T,Y lie on same circle, ∴ they are concyclic.
View full question & answer
Question 72 Marks
In figure 3.98, seg AB is a diameter of a circle with centre O . The bisector of∠ ACB intersects the circle at point D. Prove that, seg AD ≅seg BD.

Complete the following proof by filling in the blanks.
Proof: Draw seg OD.
$\angle ACB =\square \ldots 90^{\circ} \ldots \ldots \ldots . . \text { angle inscribed in semicircle }$
$\angle DCB =\square \ldots . . .45^{\circ} \ldots CD \text { is the bisector of } \angle C$
$m (\operatorname{arc} DB )=\square . . . .45^{\circ} \ldots \text { inscribed angle theorem }$
$\angle DOB =\square \ldots . . . .90^{\circ} \text { definition of measure of an arc (I) }$
$\operatorname{seg} OA \cong \operatorname{seg} OB \ldots \ldots . . \text { radii of the circle... } \square \text { (II) }$
$\therefore \text { line } OD \text { is } \square \text { of seg } AB . \ldots . . \text { bisector.... From (I) and (II) }$
$\therefore \text { seg } AD \cong \operatorname{seg} BD$
Answer
Proof: Draw seg OD.
∠ ACB = 90° {angle inscribed in semicircle}
∠ DCB = 45° {CD is the bisector of $\angle C _3$}
m(arc DB) = 45° {inscribed angle theorem}
∠ DOB = 90° {definition of measure of an arc} (I)
seg OA ≅seg OB {radii of the circle}(II)
∴line OD is bisector of seg AB From (I) and (II)
∴seg AD ≅seg BD
View full question & answer
Question 82 Marks
In figure 3.95, chord EF || chord GH. Prove that, chord EG ≅ chord FH.
Fill in the blanks and write the proof.
Proof : Draw seg GF.
∠ EFG = ∠ FGH ...Alternate interior angles.......$\square$(I)
∠ EFG = …………90° ………{inscribed angle theorem}(II)
∠ FGH = …………… 90° ………….{inscribed angle theorem} (III)
∴m(arc EG) = ……………90°…………. from (I), (II), (III).
chord EG ≅ chord FH ..........$\square$
Answer
Proof : Draw seg GF.
∠ EFG = ∠ FGH {Alternate interior angles} (I)
∠ EFG = 90°{inscribed angle theorem}(II)
∠ FGH = 90°{inscribed angle theorem} (III)
∴m(arc EG) = 90° from (I), (II), (III).
chord EG ≅ chord FH {Corresponding chords of congruent arcs of a circle (or congruent circles) are congruent}
View full question & answer
Question 92 Marks
In figure 3.92, O is the centre of a circle, chord PQ ≅ chord RS If∠ POR = 70°and (arc RS) = 80°, find -
(1) m(arc PR)
(2) m(arc QS)
(3) m(arc QSR)
Answer
m(arc PR) = ∠POR = 70°
(2) ∠POQ + ∠ QOS + ∠ROS + ∠POR = 360°
As PQ = RS, ∠ POQ = ∠ROS = 80°
⇒ ∠POQ + ∠ QOS + ∠ROS + ∠POR = 360°
⇒ 80 + ∠QOS + 80 + ∠ 70 = 360
⇒ 230 + ∠ QOS = 360
⇒ ∠QOS = 130°
m(arc QS) = ∠QOS = 130°
(3) m(arc QSR) = ∠QOS + ∠ROS = 130 + 80 = 210°
View full question & answer
Question 102 Marks
In figure 3.91, line PR touches the circle at point Q. Answer the following questions with the help of the figure.
(1) What is the sum of ∠ TAQ and∠ TSQ?
(2) Find the angles which are congruent to ∠ AQP.
(3) Which angles are congruent to ∠QTS ?
(4) ∠ TAS = 65°, find the measure of ∠TQS and arc TS.
(5) If ∠AQP = 42°and ∠SQR = 58° find measure of ∠ATS.
Answer
As TAQS is a cyclic quadrilateral,
∠TAQ + ∠TSQ = 180° (Sum of opposite angles of a cyclic quadrilateral is 180° )
(2) ∠ASQ and ∠ATQ
(3) ∠ QAS and ∠SQR
(4) ∠TAS = 65°
∠ TQS = ∠ TAS = 65° (angle by same arc TS in the same sector)
m(arc TS) = ∠TQS + ∠TAS
⇒ m(arc TS) = 65 + 65 = 130°
(5) ∠AQP + ∠AQS + ∠SQR = 180°
⇒ 42 + ∠AQS + 58 = 180
⇒ ∠AQS + 100 = 180
⇒ ∠AQS = 80
∠ AQS + ∠ ATS = 180° (opposite angles of a cyclic quadrilateral)
⇒ 80 + ∠ATS = 180
⇒ ∠ATS = 100°
View full question & answer
Question 112 Marks
In figure 3.89, line l touches the circle with centre O at point P. Q is the mid point of radius OP. RS is a chord through Q such that chords RS || line l. If RS = 12 find the radius of the circle.
Answer
The radius of the circle will bisect the chord RS. Therefore, RQ = QS = 1/2 × 12 = 6
Let the radius of circle be r,
Now, in Δ OQS, we have,
RQ = 6
OR = r
OQ = 1/2 r
Applying Pythagoras theorem, we get,
${l}r^2=\left(\frac{r}{2}\right)^2+(6)^2 $
$ r^2-\frac{r^2}{4}=36 $
$ \frac{3 r^2}{4}=36$
$3 r^2=4 \times 36$
$r^2=4 \times 12=48$
$r=\sqrt{ } 48 \text { units }$
View full question & answer
Question 122 Marks
In figure 3.85, $\square ABOC$ is a parallelogram. It circumscribes the circle with cnetre T. Point E,F, G, H are touching points. If AE = 4.5,EB = 5.5, find AD.
Answer
Given: AE = 4.5, EB = 5.5
Here, AE = AH = 4.5 {tangents from same external point are equal}
EB = BF = 5.5{tangents from same external point are equal}
∵ Opposite sides of a parallelogram are equal
∴ AE = DG and EB = GC
Also, DH = DG = 4.5{tangents from same external point are equal}
And FC = GC = 5.5 {tangents from same external point are equal}
⇒ AD = AH + HD = 10
View full question & answer
Question 132 Marks
In figure 3.84, O is the centre of the circle. Seg AB, seg AC are tangent segments. Radius of the circle isr and l(AB) = r , Prove that, $\square ABOC$is a square.
Answer
Given: AB = r = radius of the circle
Here, AB = AC = r {tangents from the same external point are equal}
And OB = OC = r = radius of the circle.
⇒ ∠ OBA = ∠ OCA = 90° Using tangent-radius theorem which states that a tangent at any point of a circle is perpendicular to the radius at the point of contact.
∵ sides of ABOC are equal and opposite angles are 90° each
Hence, ABOC is a square.
View full question & answer
Question 142 Marks
In figure 3.76, seg PQ is a diameter of a circle with centre O. R is any point on the circle. seg RS⊥seg PQ.
Prove that, SR is the geometric mean of PS and SQ. [That is, SR² = PS ×SQ]
Image
Answer
Write the proof with the help of the following steps.
(1) Draw ray RS. It intersects the circle at T.
(2) Show that RS = TS.
(3) Write a result using theorem of intersection of chords inside the circle.
(4) Using RS = TS complete the proof.
View full question & answer
Question 152 Marks
Prove that, if two lines containing chords of a circle intersect each other outside the circle, then the measure of angle between them is half the difference in measures of the arcs intercepted by the angle.
View full question & answer
Question 162 Marks
A, B, C are any points on the circle with centre O.
(i) Write the names of all arcs formed due to these points.
(ii) If m arc (BC) = 110° and m arc (AB) = 125°, find measures of all remaining arcs.
Answer
(i) Names of arcs - arc AB, arc BC, arc AC, arc ABC, arc ACB, arc BAC
(ii) m(arc ABC) = m(arc AB) + m(arc BC)
= 125° + 110° = 235°
m (arc AC) = 360° - m (arc ACB)
= 360° - 235° = 125°
Similarly, m(arc ACB) = 360° - 125° = 235°
and m(arc BAC) = 360° - 110° = 250°
View full question & answer
Question 172 Marks
In the adjoining figure circle with centre D touches the sides of ∠ ACB at A and B. If ∠ ACB = 52°, find measure of ∠ ADB.
Answer
Solution is as follows:
Image
View full question & answer
Question 182 Marks
In the adjoining figure line PA is tangent at point A. Line PBC is a secant. If AP = 15 and BP = 10, find BC.
Image
Answer
12.3 units
View full question & answer
Question 192 Marks
In the adjoining figure, chord PQ and chord AB intersect at point M. If PM = AM, then prove that BM = QM.
Image
Answer
self
View full question & answer
Question 202 Marks
Tangents drawn at points A and C of a circle intersect each other in point P. If $\angle$APC = 50°, then find $\angle$ABC.
Image
Answer
65°
View full question & answer
Question 212 Marks
In the adjoining figure, O is the centre of the circle. Find the value of $\angle$ABP if $\angle$POB = 90°
Image
Answer
45°
View full question & answer
Question 232 Marks
In the adjoining figure, A circle with centre 'O' arc PQ = arc QR = arc PR. Find measure of each of above arcs.
Image
Answer
120°
View full question & answer
Question 242 Marks
The radii of two circles are 25 cm and 9 cm. The distance between their centres is 34 cm. Find the length of the common tangent segment to these circles.
Answer
30 units
View full question & answer
Question 252 Marks
In the adjoining figure circles with centres A and C touch internally at point T. Line AB is tangent to the smaller circle at point P. Point B lies on the bigger circle. Radii are 16 cm and 6 cm. Find AP.
Image
Answer
8 units
View full question & answer
Question 262 Marks
The circles which are not congruent touch externally. The sum of their areas is $130 \pi cm ^2$ and distance between their centres is 14 cm. Find the radii of the two circles.
Answer
11 cm, 3 cm
View full question & answer
Question 272 Marks
In the adjoining figure, O is the centre and seg AB is a diameter. At point C on the circle, the tangent CD is drawn. Line BD is tangent at B. Prove that seg OD || seg AC.
Image
Answer
self
View full question & answer
Question 282 Marks
Two tangents TP and TQ are drawn to a circle with centre $O$ from an external point T. Prove that $\angle PTQ =2 \angle OPQ$.
Answer
self
View full question & answer
Question 292 Marks
A circle with centre. O Point A is in the exterior of the circle. Line AP and line AQ are tangents at point P and point Q respectively P-A-S, Q-A-R $\angle$PAR = 130°. Find $\angle$AOP.
Image
Answer
65°
View full question & answer
Question 302 Marks
In the adjoining figure, point A is the centre of the circle AN = 10 cm. Line NM is tangent at M. MN = 5cm. Find the radius.
Image
Answer
$5 \sqrt{3}$
View full question & answer
Question 312 Marks
In the adjoining figure, point P is the centre of the circle and line AB is the tangent to the circle at T. The radius of the circle is 6 cm. Find PB if $\angle TPB =60^{\circ}$.
Image
Answer
12
View full question & answer
Question 402 Marks
In figure 3.89, line l touches the circle with centre O at point P. Q is the mid point of radius OP. RS is a chord through Q such that chords RS || line l. If RS = 12 find the radius of the circle.
Image
View full question & answer
Question 422 Marks
In figure 3.84, O is the centre of the circle. Seg AB, seg AC are tangent segments. Radius of the circle isr and l(AB) = r , Prove that, $\square$ ABOC is a square.
Image
View full question & answer
Question 432 Marks
In figure 3.76, seg PQ is a diameter of a circle with centre O. R is any point on the circle. seg RS⊥seg PQ.
Prove that, SR is the geometric mean of PS and SQ. [That is, SR² = PS ×SQ]
Image
View full question & answer
Question 442 Marks
Prove that, if two lines containing chords of a circle intersect each other outside the circle, then the measure of angle between them is half the difference in measures of the arcs intercepted by the angle.
View full question & answer
Question 462 Marks
A, B, C are any points on the circle with centre O.
(i) Write the names of all arcs formed due to these points.
(ii) If m arc (BC) = 110° and m arc (AB) = 125°, find measures of all remaining arcs.
View full question & answer
Question 472 Marks
In the adjoining figure circle with centre D touches the sides of ∠ ACB at A and B. If ∠ ACB = 52°, find measure of ∠ ADB.
View full question & answer
Question 482 Marks
In figure 3.52 , chords $\mathrm{PQ}$ and $\mathrm{RS}$ intersect at $\mathrm{T}$.
(i) Find $m$ (arc SQ) if $m \angle \mathrm{STQ}=58^{\circ}, m \angle \mathrm{PSR}=24^{\circ}$.
(ii) Verify,
$\angle \mathrm{STQ}=\frac{1}{2}[m(\operatorname{arc} \mathrm{PR})+m(\operatorname{arcSQ})]$
(iii) Prove that :
$\angle \mathrm{STQ}=\frac{1}{2}[m(\operatorname{arc} \mathrm{PR})+m(\operatorname{arcSQ})]$ for any measure of $\angle \mathrm{STQ}$.
(iv) Write in words the property in (iii).

Image

View full question & answer
Question 492 Marks
Two tangents TP and TQ are drawn to a circle with centre $O$ from an external point T. Prove that $\angle PTQ =2 \angle OPQ$.
View full question & answer
Question 502 Marks
The radii of two circles are 25 cm and 9 cm. The distance between their centres is 34 cm. Find the length of the common tangent segment to these circles.
View full question & answer
Question 512 Marks
The circles which are not congruent touch externally. The sum of their areas is $130 \pi cm ^2$ and distance between their centres is 14 cm. Find the radii of the two circles.
View full question & answer
Question 522 Marks
Tangents drawn at points A and C of a circle intersect each other in point P. If $\angle$APC = 50°, then find $\angle$ABC.
Image
View full question & answer
Question 532 Marks
In the adjoining figure, point P is the centre of the circle and line AB is the tangent to the circle at T. The radius of the circle is 6 cm. Find PB if $\angle TPB =60^{\circ}$.
Image
View full question & answer
Question 542 Marks
In the adjoining figure, point A is the centre of the circle AN = 10 cm. Line NM is tangent at M. MN = 5cm. Find the radius.
Image
View full question & answer
Question 552 Marks
In the adjoining figure, O is the centre of the circle. Find the value of $\angle$ABP if $\angle$POB = 90°
Image
View full question & answer
Question 562 Marks
In the adjoining figure, O is the centre and seg AB is a diameter. At point C on the circle, the tangent CD is drawn. Line BD is tangent at B. Prove that seg OD || seg AC.
Image
View full question & answer
Question 572 Marks
In the adjoining figure line PA is tangent at point A. Line PBC is a secant. If AP = 15 and BP = 10, find BC.
Image
View full question & answer
Question 582 Marks
In the adjoining figure circles with centres A and C touch internally at point T. Line AB is tangent to the smaller circle at point P. Point B lies on the bigger circle. Radii are 16 cm and 6 cm. Find AP.
Image
View full question & answer
Question 592 Marks
In the adjoining figure, chord PQ and chord AB intersect at point M. If PM = AM, then prove that BM = QM.
Image
View full question & answer
Question 602 Marks
In the adjoining figure, A circle with centre 'O' arc PQ = arc QR = arc PR. Find measure of each of above arcs.
Image
View full question & answer
Question 622 Marks
A circle with centre. O Point A is in the exterior of the circle. Line AP and line AQ are tangents at point P and point Q respectively P-A-S, Q-A-R $\angle$PAR = 130°. Find $\angle$AOP.
Image
View full question & answer