Let the sides of triangle are a, b, c

When a, b and c are the sides of triangle and s is the semi-perimeter, then its area is given by:

A = where [Heron’s Formula]

A’ = where [Heron’s Formula]

When each side of triangle is doubled

= = 2

A’ =

A’ = = 4= 4A

Increase in area = 4A-A = 3A

Percentage increase in area = = = 300%