Area of a Circle. The area A of a circle equals the product of π and the square of its radius r. When finding the area of a circle, you have to use the.

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Presentation transcript:

Area of a Circle

The area A of a circle equals the product of π and the square of its radius r. When finding the area of a circle, you have to use the button on your calculator. You can not use an approximation of. Do not use 3.14 for pi.

Example 1 Find the area of the circle. Round your answer to the nearest hundredth. 2 in. You can not use the approximation 3.14 for pi because it won’t give you the same rounded answer. The area of the circle is square inches. PEMDAS – you solve exponents first before you multiply by pi

Example 2 Find the area of the circle. Round your answer to the nearest hundredth. 28 cm. You are given the diameter, but you will need to find out what the radius is to use the area formula. The area of the circle is square centimeters.

Example 3 Find the area of the face of the Virginia quarter with a diameter of 24 millimeters. Round your answer to the nearest hundredth. The area of the Virginia quarter is

Practice Problems 1.Find the area of a circle with a radius of 3.2 centimeters. Round your answer to the nearest hundredth. 2.The bottom of a circular swimming pool with a diameter of 30 feet is painted blue. How many square feet are blue? Round your answer to the nearest hundredth. The area of the circle is The area of the circle is