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.
We have a triangle ΔABC,
In which D and E are points on the sides AB and AC respectively.
Now For the following case we have to show that DE ∥ BC
It is given that AD = 5.7 cm, BD = 9.5 cm, AE = 3.3 cm, and EC = 5.5 cm.
learning CBSE maths in efficient way
RD sharma, DHANPAT RAI publication
Class 10th, triangle
Given:
Length of side AD = 5.7 cm, BD = 9.5 cm, AE = 3.3 cm, and EC = 5.5 cm
To show: Side DE is parallel to BC (DE || BC)
Now,
Length of side AD/BD = 5.7/9.5 = 3/5 – equation 1
And,
Length of side AE/CE = 3.3/5.5 = 3/5 – equation 2
Now from equation 1 and 2
AD/BD = AE/CE
So, by the converse of Thale’s Theorem
We get, DE ∥ BC.
Hence, Proved