Question

fimd the area of triangle whose sides are 18cm, 14cm, and 10cm, by using herons formula ​

Answer 1

Answer:

$semiperimeter \: \: (s) =( a + b + c) \div 2$

$s = (18 + 14 + 10) \div 2$

$s = 42 \div 2$

$s = 21$

$by \: herons \: formula$

$area = \sqrt{s(s - a)(s - b)(s - c)}$

$area = \sqrt{21(21 - 18)(21 - 14)(21 - 10)}$

$area = \sqrt{21 \times 3 \times 7 \times 11}$

$area = \sqrt{3 \times 7 \times 3 \times 7 \times 11}$

$area =3 \times 7 \sqrt{11}$

$area = 21 \sqrt{11} cm {}^{2}$