Area of a circle

Area, Circle
One of the most common questions related to the area of a circle is why its formula is . Let's explore this together!
  • The first slider will divide the circle into equal numbers of sectors.
  • Slide Step1 to break the circle apart.
  • Slide Step2 to align the sectors.
  1. Try different numbers of sectors, performing steps 1 and 2. As you shift to a larger number of sectors, what shape seems to be appearing? Check the "Outline the area" box to help.
  2. Now that you recognize a shape that it approaches, what is the generic formula for that shape?
  3. What parts of the circle represent the parts needed to find the area of this new shape? Check the "What is the width?" and "What is the length?" boxes. To verify.
  4. Calculate the area using the alternate shape's formula. How does this help us better understand the area of a circle?