Question

What is the formula for heron's?

Answer 1

Herons formula gives the area of a triangle when the lengths of three sides of a triangle are given.
Let the sides of the triangle are a, b and c. Let s be half the perimeter or 

$s = \frac{a+b+c}{2}$

Then area of the triangle is given by

$A= \sqrt{s(s-a)(s-b)(s-c)}$

Answer 2

the whole square root of - s(s-a)(s-b)(s-c)

where a,b,c are sides of triangle and s is the semiperimeter - s=a+b+c whole divided by2