Printable Complementary and Supplementary Angles Practice Sheet

📚 Topic Summary

Complementary angles are two angles that add up to $90^{\circ}$. Think of it as a right angle split into two smaller angles. Supplementary angles, on the other hand, are two angles that add up to $180^{\circ}$. This is like a straight line divided into two angles. Knowing these definitions helps you solve all sorts of geometry problems!

🧠 Part A: Vocabulary

Match the term with its definition:

1. Acute Angle
2. Obtuse Angle
3. Right Angle
4. Complementary Angles
5. Supplementary Angles

Definitions:

1. Two angles whose sum is $180^{\circ}$
2. An angle whose measure is greater than $90^{\circ}$ but less than $180^{\circ}$
3. An angle whose measure is $90^{\circ}$
4. An angle whose measure is less than $90^{\circ}$
5. Two angles whose sum is $90^{\circ}$

✍️ Part B: Fill in the Blanks

Complete the following sentences:

Two angles are considered __________ if the sum of their measures is $90^{\circ}$. Two angles are considered __________ if the sum of their measures is __________. A __________ angle measures less than $90^{\circ}$, while an __________ angle measures greater than $90^{\circ}$ but less than $180^{\circ}$. A straight angle measures __________.

🤔 Part C: Critical Thinking

Explain in your own words how knowing whether two angles are complementary or supplementary can help you find the measure of an unknown angle.