What is the radius of a circle if the area and circumference have the same value?

Question

I'm not only looking for an answer, but also how to work it out. Thanks!

pi r^2 = 2 pi r

Answer 1

πr² = 2πr

So, r² = 2r

r² - 2r = 0

r(r-2) = 0

r = 0 or r = 2

Since the radius is positive, r must equal 2.