The three sides of a triangle are 7 cm, 9 cm and 8 cm. What is the area of the triangle?

$12\sqrt{5}$ sq.cm

We know that,

Area of a triangle = \(\sqrt {s(s-a)(s-b)(s-c) }\)

and semi perimeter = \(\frac{a + b + c}{2}\)

Length of the three sides of the triangle: 7 cm, 9 cm, and 8 cm

So,

Semi perimeter = \(\frac{7 + 9 + 8}{2}\) = 12

Area of a triangle = \(\sqrt {12(12-7)(12-9)(12-8) }\)

=  \(\sqrt {12(5)(3)(4) }\) = 12\(\sqrt {5}\)