Naming and Measuring Angles

​Naming and Measuring Angles

By Nico Calunia

REVIEW

Open Ended

What is the difference between a LINE and a RAY?
Hint: You may use these words - line, ray, arrows, direction

Objectives:

We will...

• name angles using its vertex or usiing 3 letters

• measure angles using a protractor

Multiple Choice

What geometric figure uses this "∠" symbol?

• square

• triangle

• angle

• line

Open Ended

Where have you seen angles in real life?

Naming Angles

Summary

• The sides of an angle are made of rays.

• ​Points can be found inside (interior region), outside (exterior region) or on the angle itself.

​Sides and Regions

• An angle is formed by 2 rays with a common endpoint.

• ​An angle is named using its vertex (1 letter) or with

  3 letters (vertex in the middle).

​Form and Name

Multiple Choice

How many rays are needed to form an angle?

• 2
• 1
• 3
• 4

Multiple Choice

What is the name of the common endpoint of an angle?

• Angle Point
• Angle Corner
• Angle Base
• Vertex

Multiple Select

How many letters are used to name an angle?

Check all that applies.

• 1 letter

• 2 letters

• 10 letters

• 3 letters

Multiple Choice

Is ∠XYZ the same as ∠ZYX?

• Yes

• No

Multiple Select

What are the possible names of this angle? Check all that applies.

• ∠A

• ∠CBA

• ∠ABC

• ∠B

Multiple Select

What are the possible names of this angle? Check all that applies.

• ∠EDC

• ∠DEC

• ∠D

• ∠E

Multiple Choice

Does Y lie in the interior or in the exterior of ∠VWX?

• interior

• exterior

• neither

Multiple Choice

Analyze:
If points D, E, and F form an angle with E as the vertex, how would you write this angle?

• ∠EFD
• ∠FDE
• ∠DEFJ
• ∠DEF

Measuring Angles

Match

Match the illustrations with the kind of angles.

right angle

acute angle

obtuse angle

• right angle

• acute angle

• obtuse angle

How to use a protractor?

1. ​Place the midpoint of protractor at the vertex.

2. Align one ray with the zero line.

3. Read the number on the correct scale (inner or outer).

Multiple Choice

What is the measurement of this angle?

• 150°

• 90°

• 180°

• 120°

Multiple Choice

What is the measurement of this angle?

• 150°

• 90°

• 180°

• 120°

Multiple Choice

What is the measurement of this angle?

• 115°

• 70°

• 130°

• 100°

Multiple Choice

What is the measurement of this angle?

• 60°

• 125°

• 65°

• 70°

Multiple Choice

What is the measurement of this angle?

• 130°

• 145°

• 160°

• 35°

Multiple Choice

What is the measurement of this angle?

• 45°

• 90°

• 120°

• 60°

Multiple Choice

What is the measurement of this angle?

• 35°

• 90°

• 45°

• 60°

Multiple Choice

What is the measurement of this angle?

• 30°
• 90°
• 60°
• 45°

Paper Work

Reorder

Reorder the following:
How to Use a Protractor

• Place midpoint of protractor at vertex.

• Align one ray with the zero line.

• Read the number on the correct scale.

1

2

3

• 1
• 2
• 3

Open Ended

CLOSING: What is the use of a protractor?