# How do you use Heron's formula to find the area of a triangle with sides of lengths #3 #, #7 #, and #7 #?

##### 1 Answer

Feb 28, 2016

The area is

#### Explanation:

Heron's formula is

The semi-perimeter is half the perimeter, with the formula

Let

**Solution**

Determine semi-perimeter, then substitute known values into Heron's formula and solve.