Question

Find the area of equilateral triangle whose side is 6 cm

Answer 1

$area = \frac{1}{2} \times base \times height \\ base = 6cm \: \\ heiht = 3 \sqrt{5} \\ so \: \: \: area \: = \frac{1}{2} \times 6 \times 3 \sqrt{5} cm ^{2} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 9 \sqrt{5 \: {cm}^{2} }$