Area of a circle Investigation
Step 1:  Draw the radius squares.
Step 2:  What is the area of each radius square?
Step 3:  Before filling in each area of the quarter circles, estimate how many square units fill that space.  Check your estimate by clicking the "fill area" box when you're ready.
Step 4:  Explore- how many radius squares fill the entire circle?  Drag the outer areas of the radius squares into the white section of the circle.  Try not to overlap pieces.