Circumference and Area of a Circle

To calculate the circumference (which is like perimeter) and the area of a circle, you need a special irrational number: pi. Pi is the ratio of the circumference of a circle to its diameter. Watch this lecture series to explore the circumference and area of circles, and complete the interactive exercises.

Practice

Area of parts of circles - Questions

1. 



Find the area of the shape.

Either enter an exact answer in terms of \pi or use 3.14 for \pi and enter your answer as a decimal.

________ units ^{2}

2. 



Find the area of the semicircle.

Either enter an exact answer in terms of \pi or use 3.14 for \pi and enter your answer as a decimal.

________ units ^{2}

3. 



Find the area of the semicircle.
Either enter an exact answer in terms of \pi or use 3.14 for \pi and enter your answer as a decimal.

________ units ^{2}

4. 



Find the area of the shape.
Either enter an exact answer in terms of \pi or use 3.14 for \pi and enter your answer as a decimal.

________ units ^{2}