Geometry 1-3 Measuring and Constructing Angles. Vocabulary Angle- a figure formed by two rays, or sides, with a common endpoint. Vertex- The common endpoint.

Presentation on theme: "Geometry 1-3 Measuring and Constructing Angles. Vocabulary Angle- a figure formed by two rays, or sides, with a common endpoint. Vertex- The common endpoint."— Presentation transcript:

1 Geometry 1-3 Measuring and Constructing Angles

2 Vocabulary Angle- a figure formed by two rays, or sides, with a common endpoint. Vertex- The common endpoint of an angle (plural: vertices). Interior of an angle- all points between the sides of an angle. Exterior of an angle- all points outside of the sides of an angle. Degree- the unit of measure for angles.

3 Naming Angles Angles can be named three ways: 1.By its vertex R 2.By a number 1 3.By a point on each ray and the vertex SRT or TRS S R T 1

4 Name the Marked Angle A R L W 2

5 Acute angle: 1° to 89 ° Right angle: 90 ° Obtuse angle: 91 ° to 179 ° Straight angle: 180 ° Types of Angles

6 More Vocab. Congruent angles- angles that have the same measure. Angle bisector- A ray that divides an angle into two congruent angles Congruent angles: ARW  LRW Angle bisector: RW A R L W 45°

7 Postulate Angle Addition Postulate: If S is in the interior of PQR, then m PQS + m SQR = m PQR (part 1 + part 2 = the whole) R Q S P

8 Example What is the measure of angle WRL? A R L W T 45° 65°

9 Example If Y is in the interior of LMN, find the m LMY if m LMY = 5x+3, m YMN = 3x+3, and m LMN=86°.

10 Using a Protractor wxvzxw YXZ