Question

What is the area of an equilateral triangle whose side is 8 cm? (nearest integer)

• A. 17
• B. 27
• C. 37
• D. 47

Answer 1

The correct option is B 27

Semi perimeter of a triangle (s) = $\frac{a+b+c}{2}$
$\Rightarrow \frac{8+8+8}{2}=12cm$
Area of a triangle = $\sqrt{s(s-a)(s-b)(s-c)}$
$=\sqrt{12(12-8)(12-8)(12-8)}$
$=\sqrt{12\times 4\times 4\times 4}$
$=\sqrt{3\times 4\times 4\times 4\times 4}$
= $16\sqrt{3}=16\times 1.7=27.2$ $c{m}^2$
Nearest integer is 27.