Question

Length of tape required to cover the edges of a semicircular disc of radius 10 cm is 

(a) 62.8 cm (b) 51.4 cm (c) 31.4 cm (d) 15.7 cm

Answer 1

(b) 51.4 cm

From the question it is given that, radius of semicircular disc 10 cm

We know that, perimeter of semicircular disc = circumference of semicircle + diameter

Circumference of semicircle = 2πr/2

= πr

= (22/7) × 10

= 31.4 cm

Then, total tape required = 31.4 + 10 + 10

= 51.4 cm