Question

A wire is looped in the form of a circle of radius $21cm$. It is rebent in the shape of an equilateral triangle. Find the area of the triangle. Take $\pi =\frac{22}{7}$

• A. $484c{m}^2$
• B. $484\sqrt{3}c{m}^2$
• C. $308c{m}^2$
• D. $308\sqrt{3}c{m}^2$

Answer 1

Answer: (B)

$484\sqrt{3}c{m}^2$

Radius of circular wire$=21cm$
circumference of wire$=2\pi r=2\times \frac{22}{7}\times 21=132cm$
perimeter of equilateral $\Delta =3a=132cm$
$a=44cm$
area of equilateral $\Delta =\frac{\sqrt{3}}{4}{a}^2=\frac{\sqrt{3}}{4}\times 44\times 44=484\sqrt{3}c{m}^2$