Question drawn from very renowned book RD sharma of class 10th, Chapter no. 4

Chapter name:- Triangles

Exercise :- 4.2

This is very important question of triangle.

In this question we have ΔABC, in which D and E are points on the sides AB and AC respectively such that DE || BC.

Also it is given that AD = 4 cm, DB = 4.5 cm and AE = 8 cm,

Now we have to find the length of AC.

learning CBSE maths in efficient way

RD sharma, DHANPAT RAI publication

Class 10th, triangle

Given:Length of side AD = 4 cm, DB = 4.5 cm, AE = 8 cm

To find: Length of side AC.

By using Thales Theorem, we get

AD/BD = AE/CE – equation 1

Now, putting values in equation 1,

4/4.5 = 8/AC

AC = (4.5 × 8)/4 cm

∴AC = 9 cm

Therefore, Length of side AC is 9 cm