## Envision Math 5th Grade Textbook Answer Key Topic 20.1 Constructing Angles

Review What You Know

Vocabulary
Choose the best term from the box. Question 1.
A ? extends in two directions infinitely.

Question 2.
A ? has one endpoint and extends in one direction, while a ? has two endpoints.

Question 3.
? lines intersect at one point and create four right angles.

Identifying Angles
Classify each angle as acute, obtuse, straight or right.
Question 4. Question 5. Question 6. Question 7. Patterns
Find the next two numbers in each pattern.
Question 8.
1.5, 1.7, 1.9, 2.1,2.3, ☐, ☐

Question 9.
26, 21,16, 11, ☐, ☐

Shapes
Writing to Explain Write an answer for each question.
Question 10.
Can a triangle have two obtuse angles?

Question 11.
Is a square always a rectangle?

Constructing Angles

How can you construct an angle congruent to another angle?
A geometric construction is the drawing of a figure using only a compass and a straightedge. A ruler and a protractor are not used in making a construction.

Question.
How would you construct ∠
B congruent to ∠M? Guided Practice

Do you know HOW?
In 1 and 2, trace each angle on a sheet of paper. Then construct an angle congruent to each given angle.
Question 1. Question 2. Do you UNDERSTAND?
Question 3.
Writing to Explain Why is it important to keep the same compass setting in Step 1?

Question 4.
How can you tell if a constructed angle is congruent to the original angle?

Independent Practice

In 5 through 7, trace each angle on a sheet of paper. Then construct an angle congruent to each given angle
Question 5. Question 6. Question 7. Problem Solving
Question 8.
The Leaning Tower of Pisa is located in Italy. It leans to the south at the angle shown in the picture below. Construct an angle congruent to ∠A. Question 9.
Mario has saved a number of quarters, nickels, dimes, and pennies. He will use $3.93 to buy a new toy for his dog. Using the fewest coins, what combination of coins will equal$3.93?

Question 10.
Justin climbed 15 steps to the second floor of a building. Each step is 8 inches high. How many feet higher is the second floor than the first? 