Question

please give me answer in this question number 13

Answer 1

The small circle:

Pi x r2 = 962.5 cm

r2 = 962.5 x 7 = 306.5 cm

22

r = square root of 306.5 = 17.5 cm

The big circle:

pi x R2 = 1386 cm

R2 = 1386 x 7 = 441 cm

22

R = square root of 441 = 21 cm

The circular ring's width = Radius of big circle - (minus) Radius of small circle = 21 - 17.5 = 3.5 cm