Question

Using Theorem 2.1, prove that a line drawn through
the mid-point of one side of a triangle parallel to
another side bisects the third side. (Recall that you
have proved it in Class IX). ​

Answer 1

Step-by-step explanation:

see the attachment

hope it helps

Answer 2

Given,In triangle ABC, D is the midpoint of AB such that AD=DB.

A line parallel to BC intersects AC at E as shown in above figure such that DE||BC.

To prove, E is the midpoint of AC.

Since, D is the midpoint of AB

So,AD=DB

⇒ AD/DB=1.....................(i)

In triangle ABC,DE||BC,

By using basic proportionality theorem,

Therefore, AD/DB=AE/EC

From equation 1,we can write,

⇒ 1=AE/EC

So,AE=EC

Hence, proved,E is the midpoint of AC.