Question

How do you use Heron's formula to determine the area of a triangle with sides of that are 15, 18, and 12 units in length?

Answer 1

`16S^2=(a+b+c)(-a+b+c)(a-b+c)(a+b-c)=(15+18+12)(-15+18+12)(15-18+12)(15+18-12)=(45)(15)(9)(21)=3(15)(15)(9)(3)(7)` or

`S ={ 9 (15)}/4 sqrt{7}={135 sqrt{7} }/4`

Explanation:

Seems a bit easier than the other answer.