For what value of "radius r" is the perimeter of a circle equal to its area?

Quickest Way:

Put Area = Circumference

Pi x r x r = 2 x Pi x r

Using Cancellation of equations,

r = 2

Important: Trial and error takes time - Cannot do while doing a grammar school exam.

Important: The same question can ask for values "less than" or "equal to"

Important: The same question can ask for permiter and area comparison of square