# 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.

\color{red}64\pi square meters

**Problem 2:** The diameter of a circle is 4.5 feet. Find its area. Use \pi = 3.1416.

## Answer

\color{red}15.90 square feet

**Problem 3:** Find the area of the circle below with a given radius. Use \pi = 3.14

## Answer

\color{red}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.

\color{red}60.00 square inches

**Problem 5:** The circumference of a circle is 22.2 feet. What is its area? Use \pi = 3.14

## Answer

\color{red}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

\color{red}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

\color{red}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

\color{red}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

\color{red}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

\color{red}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.

\color{red}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

\color{red}21\pi square inches

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