1. Three Types of Special Angles
SECTION 2.4
Three Types of Special Angles

2. 1) Complementary Angles
Complementary angles are two angles whose measures = 90o
1) Find the complement to the angle.
90o - 74o = 16o

3. 2) Supplementary Angles
Supplementary angles are two angles whose measures = 180o
2) Find the supplement to the angle.
180o - 74o = 106o

4. S = 3C S = 180o – A C = 90o – A 180o + 2A= 270o 180o – A = 3(90o – A)
Challenge Question
A supplement of an angle is three times as large as the complement of the angle.
Find the angle.
S = 3C
S = 180o – A
C = 90o – A
180o + 2A= 270o
180o – A =
3(90o – A)
2A= 90o
180o – A= 270o – 3A
A= 45o

5. Vertical Angle Theorem: 3) Vertical Angles are

6. Using Algebra to Solve for Angle Measurements
Find the measure of all the angles.
2(65) + 35 = 165o
65o - 50o
15o
y = 5
= 15o
x – x + 35 = 180o
z = 165o
3x – 15 = 180o
3x = 195o
x = 65o

7. PRACTICE
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8. Vertical Angles
THEOREM: Vertical Angles are CONGRUENT!