1. Name ___ 6__ Lesson #3 - Measuring Angles Feb__

2. EXPLORE  Page 133 – Use a standard protractor.
You will need a ruler.
➤ Use a ruler to draw an angle.
➤ Have your partner:
• use the 45°, 90°, and 180° angles above as reference angles
to estimate the size of the angle
• record the estimate
➤ Trade roles. Continue until you have 4 different angles.
Try to make angles that are acute, right, and obtuse.

3. To measure any angle, just follow these 4 steps:
Estimate - is it acute (less than 90°) OR is it obtuse (greater than 90°)?
2) Place protractor properly so the vertex (corner) of the angle is at the center of the protractor
and one arm lines up with the base line.
3) Start at 0° on the arm along the base line. Slide your finger around the arc of the protractor counting up from 0°. Find where the other arm meets the protractor. Read the measure.

4. 4) What if the angle is a reflex angle?
Measure the other side of the angle and subtract from 360º.

5. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7

6. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
1) What is the measure of each angle? Explain how you know.
a) b) c)

7. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
1) What is the measure of each angle? Explain how you know.
a) 35º b) c)

8. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
1) What is the measure of each angle? Explain how you know.
a) 35º b) 90º c)

9. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
1) What is the measure of each angle? Explain how you know.
a) 35º b) 90º c) 140º

10. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
1) What is the measure of each angle? Explain how you know.
a) 35º b) 90º c) 140º
I know these measures are correct because the protractor was placed on the horizontal arm, and I started on the scale at 0º.

11. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
2) Estimate Measurement Difference Name a) b) c) d) e) f)

12. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
2) Estimate Measurement Difference Name
a) 30º 35º º acute b) c) d) e) f)

13. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
2) Estimate Measurement Difference Name
a) 30º 35º º acute
b) 80º 76º º acute c) d) e) f)

14. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
2) Estimate Measurement Difference Name
a) 30º 35º º acute
b) 80º 76º º acute
c) 110º 115º º obtuse d) e) f)

15. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
2) Estimate Measurement Difference Name
a) 30º 35º º acute
b) 80º 76º º acute
c) 110º 115º º obtuse
d) 20º 21º º acute e) f)

16. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
2) Estimate Measurement Difference Name
a) 30º 35º º acute
b) 80º 76º º acute
c) 110º 115º º obtuse
d) 20º 21º º acute
e) 100º 107º º obtuse f)

17. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
2) Estimate Measurement Difference Name
a) 30º 35º º acute
b) 80º 76º º acute
c) 110º 115º º obtuse
d) 20º 21º º acute
e) 100º 107º º obtuse
f) 170º 165º º obtuse

18. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7 5)

19. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
5) I can tell I’m using the correct scale on the protractor, because ______________________________________________________________________________________________________

20. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
5) I can tell I’m using the correct scale on the protractor, because I start at the 0º mark on the horizontal arm. I can also tell by checking my measurement with my estimate.

21. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
6) Use a protractor to find the measure of each reflex angle.
How can you check that your measure is correct?
a) b) c)

22. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
6) Use a protractor to find the measure of each reflex angle.
How can you check that your measure is correct?
I measure the opposite angle and then subtract from 360º.
a) b) c)

23. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
6) Use a protractor to find the measure of each reflex angle.
How can you check that your measure is correct?
I measure the opposite angle and then subtract from 360º.
a) 45º So… b) c)
360º - 45º = 315º

24. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
6) Use a protractor to find the measure of each reflex angle.
How can you check that your measure is correct?
I measure the opposite angle and then subtract from 360º.
a) 45º So… b) 110º So… c)
360º - 45º = 315º 360º - 110º = 250º

25. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
6) Use a protractor to find the measure of each reflex angle.
How can you check that your measure is correct?
I measure the opposite angle and then subtract from 360º.
a) 45º So… b) 110º So… c) 165º So…
360º - 45º = 315º 360º - 110º = 250º 360º - 165º = 195º

26. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
7) Use a protractor to solve each riddle.
a) I have 4 equal angles. Each angle measures 90°. Which letter am I?
b) I do not have any angles that measure 90°. I have 3 angles that measure 60°. I have 2 angles that measure 120°. Which letter am I?
c) I have 2 right angles. I have 1 acute angle. I have 1 obtuse angle. Which letter am I?
d) Make up your own letter riddle. Trade riddles with a classmate. Solve your classmate’s riddle.

27. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
7) Use a protractor to solve each riddle.
a) I have 4 equal angles. Each angle measures 90°. Which letter am I? E or X
b) I do not have any angles that measure 90°. I have 3 angles that measure 60°. I have 2 angles that measure 120°. Which letter am I?
c) I have 2 right angles. I have 1 acute angle. I have 1 obtuse angle. Which letter am I?
d) Make up your own letter riddle. Trade riddles with a classmate. Solve your classmate’s riddle.

28. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
7) Use a protractor to solve each riddle.
a) I have 4 equal angles. Each angle measures 90°. Which letter am I? E or X
b) I do not have any angles that measure 90°. I have 3 angles that measure 60°. I have 2 angles that measure 120°. Which letter am I? A
c) I have 2 right angles. I have 1 acute angle. I have 1 obtuse angle. Which letter am I?
d) Make up your own letter riddle. Trade riddles with a classmate. Solve your classmate’s riddle.

29. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
7) Use a protractor to solve each riddle.
a) I have 4 equal angles. Each angle measures 90°. Which letter am I? E or X
b) I do not have any angles that measure 90°. I have 3 angles that measure 60°. I have 2 angles that measure 120°. Which letter am I? A
c) I have 2 right angles. I have 1 acute angle. I have 1 obtuse angle. Which letter am I? K
d) Make up your own letter riddle. Trade riddles with a classmate. Solve your classmate’s riddle.

30. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
7) Use a protractor to solve each riddle.
a) I have 4 equal angles. Each angle measures 90°. Which letter am I? E or X
b) I do not have any angles that measure 90°. I have 3 angles that measure 60°. I have 2 angles that measure 120°. Which letter am I? A
c) I have 2 right angles. I have 1 acute angle. I have 1 obtuse angle. Which letter am I? K
d) Make up your own letter riddle. Trade riddles with a classmate. Solve your classmate’s riddle. I have exactly 2 right angles. Which letter am I?

31. Name ___ 6__ Lesson #3 - Measuring Angles Jan__
PRACTICE  Pages #’s 1, 2, 5, 6, 7
7) Use a protractor to solve each riddle.
a) I have 4 equal angles. Each angle measures 90°. Which letter am I? E or X
b) I do not have any angles that measure 90°. I have 3 angles that measure 60°. I have 2 angles that measure 120°. Which letter am I? A
c) I have 2 right angles. I have 1 acute angle. I have 1 obtuse angle. Which letter am I? K
d) Make up your own letter riddle. Trade riddles with a classmate. Solve your classmate’s riddle. I have exactly 2 right angles. Which letter am I? T