Question

if the difference between the circumference and the radius of a circle is 37 cm, then find the circumference (in cm) of the circle

Answer 1

Let r be the radius of circle.
Difference between circumference and radius of circle = 37 cm
Circumference of circle = 2$\pi$r
                                      = 2 x 22/7 x r = 44/7 x r
Now,
Difference between circumference and radius of circle = 2$\pi$r - r
37 = 44/7 x r - r
37 = r(44/7-1)
37 = r(44 - 7)/7
37 = 37 / 7 x r
37 x 7/37 = r
r = 7 cm
Now , Circumference of circle = 44/7 x r
                                                 = 44/7 x 7
                                                 = 44 cm . 
∴ Circumference of circle = 44 cm

Answer 2

c-r = 37
c = 37- r
c = 2Π r
37+ r = 2*22/7*r
37+ r = 44r/7
37 = 44r/7- r = 37r/7
r = 37*7/37
r = 7 cm
c = 2*22/7*7 = 44 cm