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Angles. Angle Formation. An angle is formed by two rays that share a common endpoint . The sides of an angle are the two rays. The vertex of an angle is the common endpoint of the two rays. Naming Angles By The Vertex. You can name the angle by the vertex IF, there is only one angle.
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Angle Formation • An angle is formed by two rays that share a common endpoint. The sides of an angle are the two rays. The vertex of an angle is the common endpoint of the two rays.
Naming Angles By The Vertex • You can name the angle by the vertex IF, there is only one angle. • GOOD Bad • B Not Possible
Naming an Angle using Three Points • When using three letters to name an angle: • The letter in the center is ALWAYS the Vertex. • The letters on either side are from each side of the angle. • ZGR Or RGZ
Naming the Angle after Numbering the Vertex • If the Vertex is numbered, you can use the Number to name the Angle. • 3
Measuring an Angle • A protractor is a basic tool used to measure angles. One unit of measure for angles is degrees (º).
Writing the Measure of an Angle • When writing the Measure of an Angle we use m(angle) = degrees • mDKX = 30 degrees
Types of Angles • Acute • Right • Obtuse • Straight or Linear
Acute Angles • Angles whose Measure is greater than Zero degrees but less than ninety degrees
Right Angles • Right Angles have a measurement of ninety degrees. • ***Warning*** there ARE NO LEFT angles!!! • The word Right comes from the latinRect, NOT Your hand.
Obtuse Angles • Obtuse angles are greater than ninety degrees but less than one-hundred eighty degrees.
Straight angles, linear angles • Straight angles, linear angles have a measure of one-hundred eighty degrees.
Special Angles • Supplementary Angles • Complementary Angles • Perpendicular Relationships • Adjacent Angles • Linear Pair • Vertical Angles
Supplementary Angles • Two angles are supplementary angles if the sum of their angle measures is equal to 180º.
Complementary Angles • Two angles are complementary angles if the sum of their angle measures is equal to 90º.
Perpendicular Relationships • Two lines, line segments, or rays are perpendicular if they intersect to form 90º angles. The perpendicular symbol is .
Adjacent Angles • Adjacent angles are two angles that share a common vertex and share a common side.
Linear Pair • A linear pair of angles are two adjacent angles that have noncommon sides that form a line.
Vertical Angles • Vertical angles are two nonadjacent angles that are formed by two intersecting lines.