## Elementary Geometry for College Students (6th Edition)

84 $in^{2}$
Given sides of a triangle 13 in, 14 in, 15 in Using Heron's formula if three sides of a triangle have length a,b,c then area A of a triangle is A = $\sqrt s(s-a)(s-b)(s-c)$ where s = $\frac{a+b+c}{2}$ Lets take a=13 b=14 and c=15 s = $\frac{13+14+15}{2}$ = 21 in A = $\sqrt 21(21-13)(21-14)(21-15)$ =$\sqrt 21*8*7*6$ =84 $in^{2}$