The area A of a circle is pi times the radius r squared

Question

I need help with this math problem. I don't understand it.

Answer 1

Are you trying to come up with the formula from, say, a Geometry standpoint, given that we would already know how to find Circumference?
 
If so, what you can do is take a circle, and cut it up into, say, 8 equal slices.  Then lay them out side-by-side, alternating the pointed ends.  The more slices you make, the more it will look like a rectangle.  The heighth of this 'rectangle' will be the radius of the original circle.  The base will be half the circumference: (2*pi*r)/2 = pi*r.
 
Area of a rectangle is Base * Height, so (pi*r)*(r) = (pi)r2.
 
What class are you taking?