190 likes | 331 Views
Angle Measure. Sec: 1.4. Angles. Are formed By two non-collinear rays. They have a common endpoint. The two rays are called sides of an angle. The common endpoint is the vertex. Side. B. Vertex. A. C. Side.
E N D
Angle Measure Sec: 1.4
Angles • Are formed By two non-collinear rays. • They have a common endpoint. • The two rays are called sides of an angle. • The common endpoint is the vertex. Side B Vertex A C Side
There are three ways to name an angle(1) Using 3 points, (2) Using 1 point (3) Using a number – next slide A C B Lesson 1-4: Angles
Naming an Angle - continued Using a number: A B 2 C Lesson 1-4: Angles
Example 1 • Name the following angle. B A 4 C
Example 2Name the different angles Lesson 1-4: Angles
Example 3Name the angles • K is the vertex of more than one angle. Therefore, there is NO in this diagram. Lesson 1-4: Angles
Notes - Angle and Points • Angles can have points in the interior, in the exterior or on the angle. E A D B C Points A, B and C are on the angle. D is in the interior and E is in the exterior. B is the vertex. Lesson 1-4: Angles
Example 4 Name all angles with B as a vertex. 2. Name the sides of angle 5. 3. Write another name for angle 6.
Classifying Angles: D A B C
Example 5 Classify each angle as right, obtuse, acute or straight. 1. Angle TYV 2. Angle WYT 3. Angle TYU 4. angleTYX
Congruent angles • Two angles with the same angle measure are said to be congruent. Example:
Angle Addition Postulate Postulate: The sum of the two smaller angles will always equal the measure of the larger angle. Complete: m ____ + m ____ = m _____ MRK KRW MRW Lesson 1-4: Angles
Example 6 m1 + m2 = Therefore, mADC = Lesson 1-4: Angles
Example 7: Angle Addition K is interior to MRW, m MRK = (3x), m KRW = (x + 6) and mMRW = 90º. Find mMRK. Lesson 1-4: Angles
Example 8:Angle Addition K is interior to MRW, m MRK = (2x + 10), m KRW = (4x - 3) and mMRW = 145º. Find mMRK and m KRW. Lesson 1-4: Angles