Answer
126 m$^{2}$
Work Step by Step
A = $\sqrt {s(s−a)(s−b)(s−c)}$, where s = $\frac{1}{2}$(a+b+c)
a = 15
b = 17
c = 21
To simplify the equation and to make the computation process easier, solve for "s" first.
s = $\frac{1}{2}$(a+b+c) = $\frac{1}{2}$(15+17+21) = $\frac{1}{2}$(53) = 26.5
Now, substitute 26.5 into the original equation every time "s" appears.
A = $\sqrt {s(s−a)(s−b)(s−c)}$
A = $\sqrt {26.5(26.5−a)(26.5−b)(26.5−c)}$
A = $\sqrt {26.5(26.5−15)(26.5−17)(26.5−21)}$
A = $\sqrt {26.5(11.5)(9.5)(5.5)}$
A = $\sqrt {15,923.1875}$
A ≈ 126. 2
126.2 rounded to the nearest whole number is 126.
