Question

The area of a circle is 24.64 m². The circumference of the circle is

(a) 14.64 m
(b) 16.36 m
(c) 17.60 m
(d) 18.40 m

Answer 1

(c) 17.60 m

Let the radius of the circle be r m.
Area = ${\mathrm{\pi r}}^2$ m²
∴ ${\mathrm{\pi r}}^2$ = 24.64
⇒ $\left(\frac{22}{7}\times r\times r\right)$ = 24.64
⇒ r² = $\left(\frac{24.64\times 7}{22}\right)$ = 7.84
⇒ r = $\sqrt{7.84}$ = 2.8 m
⇒ Circumference of the circle = $\left(2\mathrm{\pi r}\right)$ m
= $\left(2\times \frac{22}{7}\times 2.8\right)$ m = 17.60 m