# Angle Measure - PowerPoint PPT Presentation

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## Angle Measure

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### Angle Measure Degree A unit of measure resulting from the division of the circumference of a circle into 360 parts. Ray A part of a line that has one endpoint ... – PowerPoint PPT presentation

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Title: Angle Measure

1
Angle Measure
• Degree A unit of measure resulting from the
division of the circumference of a circle into
360 parts.
• Ray A part of a line that has one endpoint and
extends infinitely in one direction. Rays are
named by stating the endpoint first and then any
other point on the ray. Rays are labeled using a
one-directional arrow.

2
Angle Measure
• Opposite Rays Two rays determined by choosing a
point on a line. Thus, these rays share a common
endpoint and are collinear.
• Angle A geometric figure formed by two
noncollinear rays that have the same endpoint.
• Sides The rays that form the angle.
• Vertex The common endpoint.

3
Angle Measure
• Naming an Angle An angle is named using either
its vertex, its vertex and a point on each ray,
or a numerical label.
• Labeling an Angle When labeling an angle, use
the ? symbol in front of the angles name. When
mentioning an angles measure, use an m in front
of the ? to indicate measure.

4
Example 4-1d
Answer ?1, ?2, ?3, and ?RXB or ?RXN
Answer ?AXB, ?AXN, ?NXA, ?BXA
5
Angle Measure
• Interior of an angle A point is in the interior
of an angle if it does not lie on the angle
itself and it lies on a segment with endpoints
that are on the sides of the angle.
• Exterior of an angle A point is in the exterior
of an angle if it is neither on the angle itself
nor in the interior of the angle.

6
Angle Measure
• Acute angle - An angle is acute if and only if
its measure is between 0 and 90 degrees.
• Right angle - An angle is a right angle if and
only if its measure equals 90 degrees.
• Obtuse angle - An angle is obtuse if and only if
its measure is more than 90 degrees and less than
180 degrees.

7
Example 4-2d