Angles

Angles – sides and vertex When two rays or line segments meet at a point, they form an angle at that point. Each of the two rays or line segments are called sides. The common endpoint is called the vertex. T S R side sides: SR and RT vertex: R vertex side

Naming Angles There are several ways to name this angle. 1) Use the vertex and a point from each side. SRT or TRS vertex side 1 T S R The vertex letter R is always in the middle. 2) Use the vertex letter only. R If there is only one angle at a vertex, then the angle can be named with that vertex. 3) Use a number. 1

Example 1 1) Name the angle in four ways. ABC CBA B 1 2) Identify the vertex and sides of this angle. vertex: Point B sides: BA and BC

Example 2 1) Name the angle in four ways. KLM MLK L 1 2) Identify the vertex and sides of this angle. vertex: Point L sides: LK and LM

Example 3 1) Name the angles. XWZ or ZWX XWY or YWX ZWY or YWZ 1 2 2) Identify the vertex and sides of this angle. vertex: Point W sides: WX, WY and WZ

Example 4 1) Name all angles having O as their vertex. POR or ROP Q P R 1 2 O POQ or QOP QOR or ROQ 1 2 2) What are other names for ? 1 POQ or QOP 3) Is there an angle that can be named ? O No!

Try these 1. Name the vertex and side of the given angle 2. Name the given angles.