# 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.

1. On the picture, draw and label a diameter.

2. 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.

1. The length of the minute hand on a clock is 5 in.

2. The distance across a sink drain is 3.8 cm.

3. The tires on a mining truck are 14 ft tall.

4. The fence around a circular pool is 75 ft long.

5. The distance from the tip of a slice of pizza to the crust is 7 in.

6. Breaking a cookie in half creates a straight side 10 cm long.

7. The length of the metal rim around a glass lens is 190 mm.

8. 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?

### 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?

(From Unit 3, Lesson 3.)