Question

A wire in the form of a rectangle 18.7 cm long and 14.3 cm wide is reshaped and bent into the form of a circle. Find the radius of the circle so formed.

Answer 1

Length of the wire = Perimeter of the rectangle
= 2(l + b) = 2 × (18.7 + 14.3) cm = 66 cm

Let the wire be bent into the form of a circle of radius r cm.

Circumference of the circle = 66 cm

⇒ $2\mathrm{\pi r}=66$
⇒ $\left(2\times \frac{22}{7}\times r\right)=66$
⇒ r = $\left(\frac{66\times 7}{2\times 22}\right)$ cm = 10.5 cm

Hence, the radius of the circle formed is 10.5 cm.