the inner circumference of a circle race track 18 m wide is 880 m . find the radius of the outer circle .
let inner radius be r metres then 2 π r = 640 2 × 22 / 7 r = 880 44 / 7 r = 880 r = 880 × 7 / 44 = 140 m answer is d .
divide(divide(880, const_pi), const_2)