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 a circle - Questions
1. Find the area of a circle with a circumference of units.
2. What is the area of the following circle?
Either enter an exact answer in terms of or use for and enter your answer as a decimal.
Either enter an exact answer in terms of or use for and enter your answer as a decimal.
4. Find the area of a circle with a circumference of units.
5. Find the area of a circle with a radius of 2.
Either enter an exact answer in terms of or use for and enter your answer as a decimal.
6. Find the area of a circle with a diameter of 4.
Either enter an exact answer in terms of or use for and enter your answer as a decimal.
7. Find the area of a circle with a circumference of units.