Lesson 4T ~ Circumference and Pi
Name__________________________________________
Period______
Date____________
Circle the correct answer.
1. The number pi is represented by what symbol?
A. 
B. 
C. 
2. Finding the circumference of a circle is like finding the __________________.
A. area of a square
B. volume of a cone C. perimeter of a square
3. The ratio of the circumference of a circle to its diameter is approximately, ________.
A. 2.14
B. 3.14
C. 4.14
Circumference of a Circle
C = d
or
C = 2r
d
r
Circle the expression that can be used to find the circumference of each circle. Use 3.14 for .
4.
5.
A. 5(3.14)
10
A. 2(3.14)(4.5)
9
B. 10(3.14)
C. 2(3.14)(10)
B. 2(3.14)(9)
C. 2(3.14)(18)
Find the circumference of each circle. Use 3.14 for .
6.
7.
4 cm
©2008 SMC Curriculum
3 ft
Oregon Focus on Surface Area and Volume
8. R has a radius that is 5 mm long. What is the circumference of the circle? Use 3.14 for .
a. Draw and label a diagram of the circle.
b. Find the circumference. Show work.
9. A circular track has a diameter of 127 m. Find the circumference of the track. Use 3.14 for .
10. A circle has a circumference of 37.68 inches. Follow the steps below to find its radius. Use
3.14 for .
_____ = d • _____
a. Fill in the blanks, using the formula C = d.
b. Solve for d by dividing both sides by 3.14.
c. What does the answer in part b represent? _____________
d. What is the length of the radius of the circle? ______
Find the missing measure in each circle. Use 3.14 for .
11. C = 47.1 m
d
12. C = 12.56 yards
r
13. A circular swimming pool has a circumference of 56.52 feet. What is the diameter of the
swimming pool?
©2008 SMC Curriculum
Oregon Focus on Surface Area and Volume