Area of a Circle
Instructions
1. Adjust the slider in order to unravel the circumference of the circle
2. Click on the 'circumference' box to show the length of the line created
3. Click on the 'dissect' button to split the circle into the given number sectors
4. Adjust the 'rearrange' slider, stopping on the x, to split open the circle, maintaining its area. Continue to adjust the slider so that the blue area folds on top of the red area so that a curve-edged parallelogram appears.
5. Adjust the 'rearrange' slider back to it starting position and adjust the red slider to split the circle into a higher number of sectors and repeat step 4. You are now left with something representing a rectangle with length half its circumference and height r. Therefore A =