Why does circle area formula work?

By Lauren and Camilla06.03.09

Problem:

• The formula for a rectangle is A = L x W• The formula for a circle is A= πr2

Process:

• First we colored in half of a circle.• Then we cut all the small segments.• Then we stuck them on the another piece of

paper so that it formed rectangle.• And a method was worked out.

Challenges:

• The challenges that we faced were that we didn’t cut the segments small enough so that the rectangle formed wasn’t exactly perfect.

• It also was difficult to work out the formula from a rectangle to a circle.

Solution:• A = L x W• A= C⁄2 x r• A= πd/2 x r• A = π2r ⁄2 xr• A = πr x r• A = πr2