Question

A uniform circular track is the area bounded by two concentric circles.If the area of track is 1144m² and its width is 14m.Find the diameter of the two circles.

Answer 1

Let the radii of inner circle be x and Thor outer circle be x+14.
We Know That,
area of the track =pi(R^2-r^2)
1144=22/7[(x+14)^2-(x)^2]
1144*7/22=[x^2+14^2+2(x)(14)]-x^2
364=x^2+196+28x-x^2
364=196+28x
364-196=28x
168=28x
168/28=x
x=6
Therefore,radius of inner circle =6m
radius of outer circle=20m
Diameter of inner circle =12m
Diameter of outer circle =40m