Question

if the circumference of circle exceeds its diameter by 30 cm find the radius of the circle

Answer 1

let the  diameter of the circle be "x' 
circumference= diameter+30
                      = x+30
radius=half of diameter
          =1/2x
(i just tried to solve answer might be wrong)

Answer 2

Circumference=2πr
Diameter=2r
2πr-2r=30
2r(π-1)=30
2r×2.14=30
r=30÷2×2.14
r=7.00 (π=3.14)