Download App

Triangle And Its Angles — MATHS STD 9 — Question

Rajasthan BoardEnglish MediumSTD 9MATHSTriangle And Its Angles1 Mark
Question
In Fig. if $\text{EC }||\text{ AB},\angle\text{ECD}=70^\circ$ and $\angle\text{ECD}=70^\circ$ and $\angle\text{BDO}=20^\circ,$ then $\angle\text{OBD}$ is:
  1. 20º
  2. 50º
  3. 60º
  4. 70º
✓

Answer

  1. 50º
Solution:
EC || AB And, CD is transverse to it.
Now $\angle\text{ECD}=\angle\text{AOD}=70^\circ$ (Corresponding angles)
 In $\triangle\text{OBD}$
$\angle\text{OBD}+\angle\text{BOD}+\angle\text{ODB}=180^\circ$
$\angle\text{BOD}=180^\circ-\angle\text{AOD}=180^\circ-70^\circ=110^\circ$
So $\angle\text{OBD}=180^\circ-\angle\text{BOD}-\angle\text{ODB}$
$=180^\circ-110^\circ-20^\circ$
$=50^\circ$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q" from Triangle And Its Angles→Triangle And Its Angles — all question types→MATHS STD 9 question papers→Rajasthan Board STD 9 question papers→Rajasthan Board question paper generator→

Similar questions

The value of $\frac{3\sqrt{12}}{6\sqrt{27}}$ is:
→
The product of difference of semi$-$perimeter and respective sides of $\triangle\text{ABC}$ are given as $13200 m^3.$ The area of $\triangle\text{ABC},$ if its semi$-$perimeter is $132m,$ is given by:
→
The graph of the linear equation y = 3x passes through the point.
→
A triangle and a parallelogram are on the same base and between the same parallels. The ratio of the areas of triangle and parallelogram is:
  1. 1 : 1
  2. 1 : 2
  3. 2 : 1
  4. 1 : 3
→
Write the correct answer in the following:
Which of the following needs a proof ?
→
AB is a chord of a circle with radius r. if P is any point on the circle such that $\angle\text{APB}$ is a right angle, then AB is equal to:
→
The perimeter of a rhombus is $20\ cm.$ If one of its diagonals is $6\ cm,$ then its area is:
→
8 is a polynomial of degree.
→
The length of the longest rod that can be fitted in cubical vessel of edge 10cm long, is:
  1. $10\text{cm}$
  2. $10\sqrt{2}\text{cm}$
  3. $10\sqrt{3}\text{cm}$
  4. $20\text{cm}$
→
$(x + y)^3 - (x - y)^3$ can be factorized as:
→