Question

Ratio of two circumference of two circle is 8:15. What is the ratio of their radii

Answer 1

the ratio of their radii is 8:15

Answer 2

Circumference of smaller circle ÷ Circumference of bigger circle = 8 ÷ 15
(2×22÷7×r)÷(2×22÷7×R) = 8÷15
r÷R = 8÷15
r : R = 8 : 15