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
Circumference of parts of circles - Questions
1.
Find the arc length of the semicircle.
Either enter an exact answer in terms of 
or use 
for and enter your answer as a decimal.
________ units
2.
Find the arc length of the partial circle.
Either enter an exact answer in terms of or use for and enter your answer as a decimal.
________ units
3.
Either enter an exact answer in terms of
or use for and enter your answer as a decimal.________ units
4.
Find the arc length of the semicircle.
Either enter an exact answer in terms of or use for and enter your answer as a decimal. units
________ units