Question

in a triangle ABC , D and E are respictively the mid points of sides AB and AC. if AD = 3cm , DE = 5cm , and AE = 3.5 cm then the perimeter of ABC is equal to

Answer 1

Answer:

20cm

Step-by-step explanation:

Given : ABC is a triangle , D and E are the mid points of AB and AC.

AD = 3.5 cm

AE = 4 cm

DE = 2.5 cm

To find : Perimeter of Δ ABC= ?

Solution :

Since D and E are the midpoints of AB and AC resp.

So, AD = DB = 3.5 cm

So,  

And, AE = EC = 4 cm

So,  

And DE is the half of BC.

So, it becomes :

So, Perimeter of Δ ABC is given by :

Hence, the perimeter is 20 cm.

Answer 2

Answer:20 cm

Step-by-step :refer image

AB=2AD (AD is the mid point of AB)

AB=2×3.5cm

AB=7cm

AC=2AE

AC=2×4cm

AC=8cm

BC=2DE (Midpoint Theorem)

BC=2×2.5cm

BC=5cm

Perimeter =AB+BC+CA

=7+5+8

=20cm