Question

Prove the area of equilateral triangle

Answer 1

it's area is 3×sides..bcoz it has it's all sides equal.

Answer 2

Let consider triangle ABC and join AD perpendicular to BC
in this triangle AB=BC=CA=a
AD=height
area of triangle ABC=underoot3 upon 4 
a² 
or 
\frac{1}{2} ah21​ah