Applied Geometry Lesson 3 1 Angles Objective Learn

Applied Geometry Lesson: 3 – 1 Angles Objective: Learn to name and identify parts of an angle.

Ray What is a ray? Opposite rays: two rays that are part of the same line and have only their endpoints in common.

Angle: a figure formed by two noncollinear rays that have a common endpoint and are not opposite rays. Vertex: the common endpoint Sides: the two rays that make up the angle

Angle… What if the rays were collinear? What would the angle look like? A B C Straight angle: the figure formed by opposite rays.

Naming Angles More than one way to name: l Name by letters (follow the lines) l Vertex l Name is always middle letter by vertex l *Warning* l Name Only use if there is one angle by number (only if given)

Name the angle in all ways

Example Name the angle in four ways. Then identify its vertex and its sides. Vertex: B Sides:

Name the whole angle in as many ways as possible Cannot use vertex to name because there are 3 angles with vertex P not one. Cannot use number to name because there is not a number that represents the whole angle.

Name all angles having W as their vertex. Do not name the same angle twice. Not asking for the different ways to name, just asking for angles.

Name all angles having W as their vertex.

Name all angles having W as their vertex.

Parts of an angle An angle separates a plane into three parts l Interior of the angle l Exterior of the angle l On the angle itself

Tell whether each point is in the interior, exterior, or on the angle. Interior On Exterior

Homework Pg. 92 1 – 8 all, 10 – 32 E