Area of a Circle Practice Problems with Answers
There are twelve (12) practice problems in this exercise about the area of the circle. You may use a calculator. Do not round intermediate calculations.
Round your final answer to two decimal places unless the exact answer is required.
For your convenience, I have included the different variations of formulas that you can use to find the area of a circle.

Problem 1: What is the area of a circle with radius 8 meters? Leave your answer in terms of \large{\pi}.
Answer
This problem requires us to leave our answer in terms of \pi.
64\pi square meters
Problem 2: The diameter of a circle is 4.5 feet. Find its area. Use \pi = 3.1416.
Answer
15.90 square feet
Problem 3: Find the area of the circle below with a given radius. Use \pi = 3.14

Answer
907.46 square centimeters
Problem 4: Find the area of the circle below with a given diameter. Use the value of \pi on your calculator.

Answer
Make sure that you use the internal value of \pi on your calculator.
60.00 square inches
Problem 5: The circumference of a circle is 22.2 feet. What is its area? Use \pi = 3.14
Answer
39.24 square feet
Problem 6: Determine the area of a dinner plate with a circumference of 37.68 inches. Use \pi = 3.14.
Answer
113.04 square inches
Problem 7: The radius of a circle is 5 inches. Find the area of the circle expressed in square centimeters c{m^2}. Use 1 in = 2.54 cm. Use \pi = 3.14.
Answer
Convert 5 inches to centimeters.

The area is
506.45 square centimeters
Problem 8: The diameter of a circle is 12.4 miles. Calculate the area of the circle in terms of square kilometers k{m^2}. Use 1 mi = 1.609 km. Use \pi = 3.1416.
Answer
Convert 12.4 miles to kilometers.

The area is
312.64 square kilometers
Problem 9: What is the radius of a circle with an area of 73.12 square miles m{i^2}? Use \large{\pi = {{22} \over 7}}.
Answer
4.82 miles
Problem 10: Determine the diameter of the circle having an area of 100 square yards y{d^2}. Use \large{\pi = {{22} \over 7}}.
Answer
11.28 miles
Problem 11: Find the area of the semicircle below with a diameter of 8 centimeters. Use \pi = 3.1416.

Answer
The area of a semicircle is half of the area of a circle.
27.33 square centimeters
Problem 12: Both circles share the same center. Find the exact area of the shaded region.

Answer
Area of the shaded region = area of the larger circle minus area of the smaller (inner) circle
21\pi square inches
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