Lesson 12: Practice Problems

Problem 1

Diego measured the diameter and circumference of several circular objects and recorded his measurements in the table.

object	diameter (cm)	circumference (cm)
half dollar coin	$3$	$10$
flying disc	$23$	$28$
jar lid	$8$	$25$
flower pot	$15$	$48$

One of his measurements is inaccurate. Which measurement is it? Explain how you know.

Problem 2

Complete the table. Use one of the approximate values for $π$ discussed in class (for example 3.14, $\frac{22}{7}$ , 3.1416). Explain or show your reasoning.

object	diameter	circumference
hula hoop	$35 in$
circular pond		$556 ft$
magnifying glass	$5.2 cm$
car tire		$71.6 in$

Problem 3 From Unit 5 Lesson 11

$A$ is the center of the circle, and the length of $C D$ is 15 centimeters.

A circle with a center A. A diameter line CD measures 15 cm. There are radius lines from A to B, E, and G

Name a segment that is a radius. How long is it?
Name a segment that is a diameter. How long is it?

Problem 4

Consider the equation $y = 1.5 x + 2$ . Find four pairs of $x$ and $y$ values that make the equation true. Plot the points $(x, y)$ on the coordinate plane.
Based on the graph, can this be a proportional relationship? Why or why not?