Question

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

Answer 1

Let $a=45;b=39,c=42$

$S=\frac{a+b+c}{2}=63$

So,

${△}^2=S(S-a)(S-b)(S-c)=63\times 18\times 24\times 21$

$△=\sqrt{63\times 18\times 24\times 21}=756c{m}^2$

Hence, this is the answer.