1. Measuring Angles Chapter 1 Section 4

2. ANGLE An angle is two rays that share a common endpoint. A B C Angles are named by a point on each side and the common endpoint. To the right is angle ABC. You can also name an angle by its vertex if it is the only angle with that vertex.

3. PARTS OF AN ANGLE SIDESIDE Vertex SIDE

4. TWO REGIONS OF AN ANGLE Interior Exterior

5. CAN YOU NAME AN ANGLE? J M L K 1 2

6. POSTULATE 1-7 PROTRACTOR POSTULATE Every angle can be paired one-to-one with an angle measure on a protractor.

7. MEASURE The measure of an angle is the absolute value of the degree paired with each of the rays.

8. 4 TYPES OF ANGLES Acute angles are less than 90 degrees Obtuse angles are greater than 90 degrees Right angles are 90 degrees Straight angles are 180 degrees

9. CONGRUENT ANGLES Congruent angles have the same angle measure. They may be marked with an arc to show congruence.

10. POSTULATE 1-8 ANGLE ADDITION POSTULATE If a ray is in the interior of an angle, the two small angles formed can be added together to get the measure of the larger angle. A B C 1 2 m1m2 ABCm

11. ON PAGE 31… Try problems #1-5 on your own. Raise your hand when you are finished.