1. Lesson 16-5 CCSS 4.MD.6, 4.MD.5.a, 4.MD.5.b, 4.G.1
Measuring Angles
Lesson 16-5
CCSS 4.MD.6, 4.MD.5.a, 4.MD.5.b, 4.G.1
Literature Link: Sir Cumference and the Great Knight of Angleland by Cindy Neuschwander 5-6 pages per day

2. MATH Essential Questions
How can lines, angles, and shapes be described, analyzed, and classified?
MATH
Essential
Questions

3. MATH Essential Questions
How are angles measured, added, and subtracted?
MATH
Essential
Questions

4. Warm Up Add the following numbers. 4,589 + 6,794 17,428 + 29,375
23, ,948

5. Think and Write
Where have you seen right angles in the real world? How do you know that they are right angles?

6. Today’s Lesson
In this lesson, you will learn how to use a protractor to measure and to draw angles.
Let’s look at the Envision Video for this lesson and take the quiz.

7. Protractors
To measure and draw angles, we use a tool called a protractor.
Where is 0 degrees?
Where is 180 degrees?

8. Angles and Protractors
It is important to use a protractor correctly. Here are some steps:
Place the protractor’s center on the vertex of the angle.
Place one side of the bottom edge on one side of the angle.
Read the measure where the other side of the angle crosses the top curved part of the protractor. If it is an acute angle use the smaller bottom number. If it is obtuse, use the top larger number.
I would model these steps on the board with a real protractor so my students can see how I would do it. I would then have them practice using their protractors.

9. Measuring Obtuse Angles
Measure the following obtuse angles using a protractor.

10. Measuring Acute Angles
Measure the following acute angles with your protractor.

11. Measuring All Angles!
Use your protractor to measure the angles. Remember to use the bottom number if the angle is acute and the top number if the angle is obtuse.

12. Lesson Wrap Up
In this lesson, you learned how to use a protractor to measure and to draw angles.
Find a friend and play the center activity – Teamwork (16-5). Check the answer key when finished to see how many you got correct.
Homework (16-5 Practice) for one “Paw Signature” and (16-5 Reteaching & Practice) if you want two “Paw Signatures.”
Website for Practice: