1. The Angle Song Enjoy

2. Objective The student will be able to: Verify by measuring and describe the relationships among vertical angles, adjacent angles, supplementary angles, complementary angles, reflex angle. SOL: 8.6(a)

3. Classification of Angles Less than 90° Equal to 90° Greater than 90° but less than 180 ° Straight Equal to 180 ° The vertex is the point where 2 lines meet. Also it is the point about which you measure an angle with a protractor.

4. Classification of Angles Complementary Angles: add up to 90° Supplementary Angles: add up to 180° Memory Aid: C comes before S, so 90 comes before 180 <a & <b are supplementary <x & <y are complementary

5. Classification of Angles Adjacent Angles: share a common side and have the same vertex Vertical Angles: are opposite angles formed by intersecting 2 lines. Vertical angles are congruent(equal). <x & <y are complementary, adjacent, and make up a right angle 1 4 3 2 <1 & <2 adjacent. <2 & <4 are not 1 4 3 2 <1 & <3 are vertical angles <2 & <4 are vertical angles

6. Classification of Angles Reflex angles: measure more than 180°

7. Angles Reflex – angles with measures greater than 180◦ and less than 360◦

8. Find a Missing Angle Measure Ex: In the figure, m<ABC = 90◦. Find the value of x. A B C D x◦ 65 ◦

9. Find a Missing Angle Measure Ex 2: Ex 3: x◦x◦ 38 ◦ x◦ 150 ◦

10. Protractor An instrument used to measure angles. Measuring Angles Applet