Question

A track is in the form of a ring whose inner and outer circumferences are 55 m and 132m respectively. Find the width of the track

Answer 1

Let the radii of the outer circle be R1 and of inner circle be R2 .

2πR1 = 132m

2πR2 = 55

Therefore, R1 = 132/2π= 21m and

R2 = 55/2π = 35/4 m.

Therefore, Width of the track = area(Outer circle) - area(inner circle)

= 2πR1^2 - 2πR2^2 = 2π(R1 ^2 - R2^2) = 2*22/7*(21^2 - (35/4)^2)

= 2*22/7*364.4375 = 2290.75 m^2.