1. Angles and Their Measures
Chapter 1 Section 1.4
Angles and Their Measures

2. Warm-Up Write the distance formula.
Find the distance between the points
(-2, 5) and (0, 7).

3. • Angle: Composed of two rays that have the same initial point B
Vertex
Exterior
Sides
Interior
The angle can be named 3 ways:

4. Name the 3 angles in the picture:

5. Congruence  Two angles are congruent if they have the same measure
If ABC  PQR then mABC = mPQR
Two segments are congruent if they have the same measure
Congruence: Having the same size and shape

6. Protractor Postulate A protractor is used to measure angles
Angles are measured using Degrees

7. Angle addition postulateR • T P
RST
RSP
PST
If P is in the interior of RST then
mRSP + mPST = m RST

8. 4 angle types A A Acute Angle Right Angle 0° < mA < 90 °• A A
Straight Angle
mA = 180 °
Obtuse Angle
90° < mA < 180 °