ABCD is a trapezium, in which AB is parallel to DC. Diagonal AC and BD intersect each other at O. If and AB = 4cm, find CD.

see full answer

Talk to JEE/NEET 2025 Toppers - Learn What Actually Works!

Real Strategies. Real People. Real Success Stories - Just 1 call away

An Intiative by Sri Chaitanya

6cm

8cm

10cm

5cm

answer is B.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

In the given trapezium, between the triangles Δ AOB and Δ COD has
$https://tex.z-dn.net/?f=%5Cfrac%7BAO%7D%7BOC%7D%20%3D%20%5Cfrac%7BBO%7D%7BOD%7D%20%3D%20%5Cfrac%7B1%7D%7B2%7D$ and ∠ AOB = ∠ COD {As they are vertically opposite angles} So, the two pairs of corresponding sides of the above two triangles are in the same ratio and their including angles are the same.
seo

Therefore, Δ AOB and Δ COD are similar triangles.
Hence, $https://tex.z-dn.net/?f=%5Cfrac%7BAB%7D%7BCD%7D%20%3D%20%5Cfrac%7B1%7D%7B2%7D$ ⇒ CD = 4 × 2 = 8 cm. {Since AB is given to be 4 cm.
We have CD IS 8cm
So, option 2 is correct.

Watch 3-min video & get full concept clarity

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET

How to Join IIT after 10th