Question

7. If the lengths of the sides of a triangle 8 cm, 11cm and 13cm then area of the triangle ___ cm2 a) 44 b) 43 c) 42.82 d) 8 root30 *

Your answer​

Answer 1

$let \: a = 8cm \: b = 11cm \: c = 13cm \\ now \: s \: = \frac{(a + b + c)}{2} = 16cm \: (s \: is \: the \: half \: perimeter) \\ \\ now \: area \: of \: \: tringle \: = \sqrt{p(p - a)(p - b)(p - c)} = \sqrt{16(16 - 8)(16 - 11)(16 - 13)} = \sqrt{16 \times 8 \times 5 \times 3} = \sqrt{1920} = 43.82 {cm}^{2}$