Question 11 Mark
In the given figure some triangles have been given. State for each triangle whether it is scalene, isosceles or equilateral. 
Questions
1 Marks Question
Take a timed test
24 questions · self-marked practice — reveal the answer and mark yourself.
View full question & answer→
Question 21 Mark
Can a triangle have: Two obtuse angles?
Answer
View full question & answer→No.
For example: Let the two angles be $120^\circ $ and $150^\circ $. Then, their sum will be $270^\circ $, which cannot form a triangle.
For example: Let the two angles be $120^\circ $ and $150^\circ $. Then, their sum will be $270^\circ $, which cannot form a triangle.
Question 31 Mark
In the given figure some triangles have been given. State for each triangle whether it is scalene, isosceles or equilateral. 
Answer
View full question & answer→Equilateral $XY = YZ = ZX = 3\ cm$
Equilateral Triangle: A triangle whose all three sides are equal in length and each of the three angles measures $60^\circ .$
Isosceles Triangle: A triangle whose two sides are equal in length and the angles opposite them are equal to each other.
Scalene Triangle: A triangle whose all three sides and angles are unequal in measure.
Equilateral Triangle: A triangle whose all three sides are equal in length and each of the three angles measures $60^\circ .$
Isosceles Triangle: A triangle whose two sides are equal in length and the angles opposite them are equal to each other.
Scalene Triangle: A triangle whose all three sides and angles are unequal in measure.
Question 41 Mark
In the given figure some triangles have been given. State for each triangle whether it is scalene, isosceles or equilateral.
Answer
View full question & answer→Isosceles
$DE = EF = 2.4\ cm$
Equilateral Triangle: A triangle whose all three sides are equal in length and each of the three angles measures $60^\circ .$
Isosceles Triangle: A triangle whose two sides are equal in length and the angles opposite them are equal to each other.
Scalene Triangle: A triangle whose all three sides and angles are unequal in measure.
$DE = EF = 2.4\ cm$
Equilateral Triangle: A triangle whose all three sides are equal in length and each of the three angles measures $60^\circ .$
Isosceles Triangle: A triangle whose two sides are equal in length and the angles opposite them are equal to each other.
Scalene Triangle: A triangle whose all three sides and angles are unequal in measure.
Question 51 Mark
In the given figure some triangles have been given. State for each triangle whether it is scalene, isosceles or equilateral.
Answer
View full question & answer→Scalene
All the sides are unequal.
Equilateral Triangle: A triangle whose all three sides are equal in length and each of the three angles measures $60^\circ .$
Isosceles Triangle: A triangle whose two sides are equal in length and the angles opposite them are equal to each other.
Scalene Triangle: A triangle whose all three sides and angles are unequal in measure.
All the sides are unequal.
Equilateral Triangle: A triangle whose all three sides are equal in length and each of the three angles measures $60^\circ .$
Isosceles Triangle: A triangle whose two sides are equal in length and the angles opposite them are equal to each other.
Scalene Triangle: A triangle whose all three sides and angles are unequal in measure.
Question 61 Mark
Fill in the blanks: The sides of a scalene triangle are of ______ lengths.
Answer
View full question & answer→The sides of a scalene triangle are of different lengths.
Question 71 Mark
Fill in the blanks: The sum of the angles of a triangle is ______.
Answer
View full question & answer→The sum of the angles of a triangle is $180^\circ$.
Question 81 Mark
Fill in the blanks: A triangle has ______ sides, ______ angles and ______ vertices.
Answer
View full question & answer→A triangle has three sides, three angles and three vertices.
Question 91 Mark
In the given figure some triangles have been given. State for each triangle whether it is scalene, isosceles or equilateral.
Answer
View full question & answer→Equilateral
All three angles are $60^\circ .$
Equilateral Triangle: A triangle whose all three sides are equal in length and each of the three angles measures $60^\circ .$
Isosceles Triangle: A triangle whose two sides are equal in length and the angles opposite them are equal to each other.
Scalene Triangle: A triangle whose all three sides and angles are unequal in measure.
All three angles are $60^\circ .$
Equilateral Triangle: A triangle whose all three sides are equal in length and each of the three angles measures $60^\circ .$
Isosceles Triangle: A triangle whose two sides are equal in length and the angles opposite them are equal to each other.
Scalene Triangle: A triangle whose all three sides and angles are unequal in measure.
Question 101 Mark
Fill in the blanks:
The sum of the lengths of the sides of a triangle is called its ______.
The sum of the lengths of the sides of a triangle is called its ______.
Answer
View full question & answer→ The sum of the lengths of the sides of a triangle is called its perimeter.
Question 111 Mark
Can a triangle have: Each angles less than $60^\circ $?
Answer
View full question & answer→No.
For example:
Let the two angles be $50^\circ $ and $40^\circ $, which on adding, gives $90^\circ .$
Thus, they cannot form a triangle whose third angle is $180^\circ - 90^\circ = 90^\circ ,$ which is greater than $60^\circ .$
For example:
Let the two angles be $50^\circ $ and $40^\circ $, which on adding, gives $90^\circ .$
Thus, they cannot form a triangle whose third angle is $180^\circ - 90^\circ = 90^\circ ,$ which is greater than $60^\circ .$
Question 121 Mark
Look at the figure given below. State for each triangle whether it is acute, right or obtuse.
Answer
View full question & answer→It is an obtuse angle triangle as one angle is $130^\circ $, which is greater than $90^\circ .$
Question 131 Mark
Look at the figure given below. State for each triangle whether it is acute, right or obtuse.
Answer
View full question & answer→It is an acute angle triangle as all the angles in it are less than $90^\circ .$
Question 141 Mark
In the given figure some triangles have been given. State for each triangle whether it is scalene, isosceles or equilateral. 
Answer
View full question & answer→Isosceles $AC = CB = 2\ cm$
Equilateral Triangle: A triangle whose all three sides are equal in length and each of the three angles measures $60^\circ .$
Isosceles Triangle: A triangle whose two sides are equal in length and the angles opposite them are equal to each other.
Scalene Triangle: A triangle whose all three sides and angles are unequal in measure.
Equilateral Triangle: A triangle whose all three sides are equal in length and each of the three angles measures $60^\circ .$
Isosceles Triangle: A triangle whose two sides are equal in length and the angles opposite them are equal to each other.
Scalene Triangle: A triangle whose all three sides and angles are unequal in measure.
Question 151 Mark
Can a triangle have: Each angles equal to $60^\circ $?
Answer
View full question & answer→Yes.
For example: Sum of all angles $= 60^\circ + 60^\circ + 60^\circ = 180^\circ .$
For example: Sum of all angles $= 60^\circ + 60^\circ + 60^\circ = 180^\circ .$
Question 161 Mark
Look at the figure given below. State for each triangle whether it is acute, right or obtuse.
Answer
View full question & answer→It is an obtuse angle triangle as one angle is $92^\circ $, which is greater than $90^\circ .$
Question 171 Mark
Draw a $\triangle\text{ABC}$. Take a point $D$ on $BC$. Join $AD$. How many triangles do you get? Name them. 
Answer
View full question & answer→In $\triangle\text{ABC},$ D is a point on $BC$ and $AD$ is joined.
Now we get triangles $\triangle\text{ABC},$ $\triangle\text{ABD}$ and $\triangle\text{ADC}.$
Now we get triangles $\triangle\text{ABC},$ $\triangle\text{ABD}$ and $\triangle\text{ADC}.$
Question 181 Mark
In the given figure some triangles have been given. State for each triangle whether it is scalene, isosceles or equilateral. 
Answer
View full question & answer→Scalene All the angles are unequal.
Equilateral Triangle: A triangle whose all three sides are equal in length and each of the three angles measures $60^\circ .$
Isosceles Triangle: A triangle whose two sides are equal in length and the angles opposite them are equal to each other.
Scalene Triangle: A triangle whose all three sides and angles are unequal in measure.
Equilateral Triangle: A triangle whose all three sides are equal in length and each of the three angles measures $60^\circ .$
Isosceles Triangle: A triangle whose two sides are equal in length and the angles opposite them are equal to each other.
Scalene Triangle: A triangle whose all three sides and angles are unequal in measure.
Question 191 Mark
Fill in the blanks: The angles opposite to equal sides of an isosceles triangle are ______.
Answer
View full question & answer→The angles opposite to equal sides of an isosceles triangle are equal.
Question 201 Mark
Fill in the blanks: Each angle of an equilateral triangle measures ______.
Answer
View full question & answer→Each angle of an equilateral triangle measures $60^\circ .$
Question 211 Mark
Can a triangle have: Each angles more than $60^\circ $?
Answer
View full question & answer→No.
For example:
Let the two angles be $70^\circ $ and $80^\circ $, which on adding, gives $150^\circ .$
They cannot form a triangle whose third angle is $180^\circ - 150^\circ = 30^\circ ,$ which is less than $60^\circ .$
For example:
Let the two angles be $70^\circ $ and $80^\circ $, which on adding, gives $150^\circ .$
They cannot form a triangle whose third angle is $180^\circ - 150^\circ = 30^\circ ,$ which is less than $60^\circ .$
Question 221 Mark
Can a triangle have: Two right angles?
Answer
View full question & answer→No.
For example:
If the two angles are $90^\circ$ each, then the sum of two angles of a triangle will be $180^\circ$, which is not possible.
For example:
If the two angles are $90^\circ$ each, then the sum of two angles of a triangle will be $180^\circ$, which is not possible.
Question 231 Mark
Look at the figure given below. State for each triangle whether it is acute, right or obtuse.
Answer
View full question & answer→It is a right angle triangle as one angle is $90^\circ .$
Question 241 Mark
Can a triangle have: Two acute angles?
Answer
View full question & answer→Yes.
For example:
Let the two angles be $50^\circ $ and $60^\circ $, which on adding, gives $110^\circ $.
They can easily form a triangle whose third angle is $180^\circ - 110^\circ = 70^\circ .$
For example:
Let the two angles be $50^\circ $ and $60^\circ $, which on adding, gives $110^\circ $.
They can easily form a triangle whose third angle is $180^\circ - 110^\circ = 70^\circ .$