Lets think back to…. ANGLE PROPERTIES

Naming Angles A 1 B C

Naming Angles OR OR M A T H 1 2

Interior = Inside A B C Exterior = Outside

ACUTE ANGLES = Greater than 0 and less than 90 RIGHT ANGLES = Measure exactly 90 OBTUSE ANGLES = Greater than 90 and less than 180 STRAIGHT ANGLES = Measure exactly 180

Why can’t you name any of the angles S? Angle Addition Postulate Why can’t you name any of the angles S? T R S P

Example 1 R T 1 P S

Example 2 M N K 2 J Y

Example 3 A U L Y

Example 4 Angle Bisector cuts the angle into 2 equal parts. C F D E

Adjacent Angles Two angles are adjacent if they share a common vertex and side, but have no common interior points. SIDE BY SIDE…shoulder to shoulder. NO YES

Linear Pairs Two adjacent angles are a linear pair if their noncommon sides are opposite rays. They form a straight line… SIDE BY SIDE…shoulder to shoulder. 1 2

Please Identify in your notes all LINEAR PAIRS h f e g j i m k

SOME POSSIBLE ANSWERS h f e g j i m k

MORE POSSIBLE ANSWERS j i m k h f e g

1. Determine whether each statement is true or false. 2 FALSE

2. 4 5 TRUE

3. 6 3 FALSE

C 4. 8 7 A T TRUE

C 5. 8 7 A T FALSE

Supplementary Angles Two angles are supplementary if the sum of their measures is 180 degrees. Each angle is the supplement of the other. 1 2 These are supplements of each other because their angles add up to 180.

Example 1 Find the value of x. This is on p. 16 of the Study Guide problem #2.

Example 2 Find the value of x. This is on p. 16 of the Study Guide problem #3.

Example 3 Find the value of x. This is on p. 16 of the Study Guide problem #3.

Complementary Angles Two angles are complementary if the sum of their measures is 90 degrees. Each angle is the complement of the other. 1 2 These are complements of each other because their angles add up to be 90.

Example 4 Find the value of x. This is on p. 16 of the Study Guide problem #1.

Example 5 Find the value of x. This is on p. 16 of the Study Guide problem #6.

1 5 2 4 3 Think back to the beginning of class… no Are angles 1 and 2 a linear pair? no Are angles 1 and 3 adjacent angles? yes Are angles 3 and 4 a linear pair? Are angles 2 and 3 adjacent angles? yes

1 5 2 4 3 Now, think of what we talked about today. no Are angles 4 and 5 supplementary angles? no Are angles 2 and 3 complementary angles? Are angles 4 and 3 supplementary angles? yes Are angles 2 and 1 complementary angles? yes