~ 7.4 ~

Solving for Unknown Angles

Learning Targets

  • I can reason through multiple steps to find unknown angle measures.

  • I can recognize when an equation represents a relationship between angle measures.

Notes

We can write equations that represent relationships between angles.

  • The first pair of angles are supplementary, so x + 42 = 180.

  • The second pair of angles are vertical angles, so y = 28.

  • The third pair of angles are complementary, so z + 64 = 90.

Activities

4.1 True or False: Length Relationships

Mathematicians refer to a length of a segment by naming its endpoints.

Check out segment AB!

Here are some line segments. Decide if each of these equations is true or false. Be prepared to explain your reasoning.

  1. CD + BC = BD

  2. AB + BD = CD + AD

  3. AC - AB = AB

  4. BD - CD = AC - AB

4.3 What’s the Match?

Match each figure to an equation that represents what is seen in the figure. For each match, explain how you know they are a match.

  1. g + h = 180

  2. g = h

  3. 2h + g = 90

  4. g + h + 48 = 180

  5. g + h + 35 = 180

Add to Your Notes

If you know that angles a and b are vertical, what equation could you use to represent this angle relationship?

  • a = b

If you know that angles c and d are complementary, what equation could you use to represent this angle relationship?

  • c + d = 90

If you know that angles e and f are supplementary, what equation could you use to represent this angle relationship?

  • e + f = 180

Assignment

Check Google Classroom!