Question

a piece of wire in the form of of a rectangle of 8.9cm long and 54 mm broadis reshaped and bent in the form of a circle. Find the radius of the circle in mm

Answer 1

perimeter of rectangle = 2 (l+b)
8.9 cm = 89mm length
54 mm breadth
2 x (89+54)
= 2 x 143 = 286 mm

Circumference of circle
2 x 22/7 x r = 286
r = 286/6.28
r= 39 mm

Area = 22/7 x 39²
= 4775 mm²