Fourth graders drill the 90° and 180° rules until they are automatic. Fill-in questions cycle through the complement of 35°, the supplement of 100°, the supplement of 25°, and the complement of 12°, with reminders that two equal supplementary angles are each 90° and two equal complementary angles are each 45°.
A matching section pairs phrases like "supplement of 40°" and "complement of 55°" with their values (140°, 35°, and more). Working through this many examples in one sitting turns the rules into reflexes — students stop counting on fingers and start spotting the answer instantly.
Style:
Angles and Measurement
Part A: Fill in the Blank
Write the missing word or number on each line.
1. The complement of a 35° angle is 55 degrees.
2. The supplement of a 100° angle is 80 degrees.
3. If two supplementary angles are equal, each measures 90 degrees.
4. An angle and its complement always add up to 90 degrees.
5. A protractor has 180 degree marks from 0° to 180°.
6. The supplement of a 25° angle is 155 degrees.
7. If two complementary angles are equal, each measures 45 degrees.
8. An angle of 89° is classified as acute because it is less than 90°.
9. The complement of a 12° angle is 78 degrees.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Supplement of 40°
→ 140°
90°
Complement of 55°
→ 35°
80°
Supplement of 90°
→ 90°
140°
Complement of 10°
→ 80°
35°
Angles and Measurement
★ Part A: Fill in the Blank
Write the missing word or number on each line.
1) The complement of a 35° angle is 55 degrees.
2) The supplement of a 100° angle is 80 degrees.
3) If two supplementary angles are equal, each measures 90 degrees.
4) An angle and its complement always add up to 90 degrees.
5) A protractor has 180 degree marks from 0° to 180°.
6) The supplement of a 25° angle is 155 degrees.
7) If two complementary angles are equal, each measures 45 degrees.
8) An angle of 89° is classified as acute because it is less than 90°.
9) The complement of a 12° angle is 78 degrees.
★ Part B: Matching
Match each item on the left to the correct answer on the right.
1) Match each item to its correct answer.
Supplement of 40°
→ 140°
90°
Complement of 55°
→ 35°
80°
Supplement of 90°
→ 90°
140°
Complement of 10°
→ 80°
35°
Ready to Practice?
Complete each section carefully.
10 Questions
10-15 minutes
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