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Learn to name and identify parts of an angle, including rays, vertices, sides, collinear rays, and more. Practice naming angles in different ways and classifying points within angles.
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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 • 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: • Name by letters (follow the lines) • Vertex is always middle letter • Name by vertex • *Warning* Only use if there is one angle • Name by number (only if given)
ExampleName 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.
Parts of an angle • An angle separates a plane into three parts • Interior of the angle • Exterior of the angle • 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