A circle has an area of M cm^2 and a circumference of N cm. If M/N=20, what is the radius of the circle in cm?

1 Answer
Aug 1, 2015

Answer:

#color(blue)(r = 40cm#

Explanation:

The formula for the area of a circle is #color(blue)(pir^2#
The formula for the circumference of a circle is #color(blue)(2pir#

The area given is : #M cm^2#

The circumference given is #N cm#

#M/N =color(blue)( (pir^2)/(2pir)) = 20#

#color(blue)( (cancelpir^2)/(2cancelpir)) = 20#

#r/2 = 20#

#color(blue)(r = 40cm#