Question

Sides of a triangle are cm 45 cm, 39 cm and 42 cm, find its area.

Answer 1

a = 45 cm
b = 39 cm
c = 42 cm
$s=\frac{a+b+c}{2}=\frac{45+39+42}{2}=63$
$$\begin{gathered} \mathrm{Area}=\sqrt{s\left(s-a\right)\left(s-b\right)\left(s-c\right)} \\ =\sqrt{63\left(63-45\right)\left(63-39\right)\left(63-42\right)} \\ =\sqrt{63\times 18\times 24\times 21} \\ =756{\mathrm{cm}}^2 \end{gathered}$$