Lesson 4
Applying Circumference
Let’s use \(\pi\) to solve problems.
Problem 1
Here is a picture of a Ferris wheel. It has a diameter of 80 meters.
![Photo of a ferris wheel.](https://staging-cms-im.s3.amazonaws.com/gMDrhQZsesZc1wRiLkTJre6r?response-content-disposition=inline%3B%20filename%3D%227-7.3.A.PP.Image.04.png%22%3B%20filename%2A%3DUTF-8%27%277-7.3.A.PP.Image.04.png&response-content-type=image%2Fpng&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAXQCCIHWF37H2AMFB%2F20240703%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240703T072250Z&X-Amz-Expires=604800&X-Amz-SignedHeaders=host&X-Amz-Signature=dff66a08431739233082685c8a09ec588409e16f8d3a43db4b1a05ecf08e8006)
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On the picture, draw and label a diameter.
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How far does a rider travel in one complete rotation around the Ferris wheel?
Problem 2
Identify each measurement as the diameter, radius, or circumference of the circular object. Then, estimate the other two measurements for the circle.
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The length of the minute hand on a clock is 5 in.
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The distance across a sink drain is 3.8 cm.
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The tires on a mining truck are 14 ft tall.
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The fence around a circular pool is 75 ft long.
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The distance from the tip of a slice of pizza to the crust is 7 in.
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Breaking a cookie in half creates a straight side 10 cm long.
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The length of the metal rim around a glass lens is 190 mm.
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From the center to the edge of a DVD measures 60 mm.
Problem 3
A half circle is joined to an equilateral triangle with side lengths of 12 units. What is the perimeter of the resulting shape?
![The figure shows a half circle and a triangle.](https://staging-cms-im.s3.amazonaws.com/7LVbaNLuhDXHdqSzXmS1uPyd?response-content-disposition=inline%3B%20filename%3D%227-7.3.A.PP.Image.05.png%22%3B%20filename%2A%3DUTF-8%27%277-7.3.A.PP.Image.05.png&response-content-type=image%2Fpng&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAXQCCIHWF37H2AMFB%2F20240703%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240703T072250Z&X-Amz-Expires=604800&X-Amz-SignedHeaders=host&X-Amz-Signature=d01dd70427b3a3baf4af6f8aa3385fee768544c52582e6d226f789d4e6b5cb5e)
Problem 4
Circle A has a diameter of 1 foot. Circle B has a circumference of 1 meter. Which circle is bigger? Explain your reasoning. (1 inch = 2.54 centimeters)
Problem 5
The circumference of Tyler's bike tire is 72 inches. What is the diameter of the tire?