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Chapter 2. Points, Lines, and Angles. Goal . Tell type of angle. Label angles. Measure angles. . Review . A? B? C?. Check . a ) ray b) line segment c) line . angle. a figure formed by the intersection of two rays. angle. Rays are called sides.
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Chapter 2 Points, Lines, and Angles
Goal • Tell type of angle. • Label angles. • Measure angles.
Check • a ) ray • b) line segment • c) line
angle • a figure • formed by the intersection • of two rays
angle • Rays are called sides. • Point where sides intersect is called a vertex.
angle • examples non-examples
Naming angles • Method 1 • angle x • angle y • Method 2 • angle ABC • angle CBA
-Angle – 2 rays that intersect -Sides – rays - Point where rays intersect – vertex - Angle ABC or CBA -Measured in degrees - 60 degrees
Right Angle Right angle • an angle • whose measure • is 90 degrees
rightangles • not rightangles
Acute angle • acute angle • an angle • whose measure • is less than 90 degrees
acute angles • not acute angles
obtuse angle • obtuse angle • an angle • whose measure is • greater than 90 degrees but • less than 180 degrees
Why are these obtuse angles? Obtuse angle
Obtuse Angles • Not Obtuse
acute • right angle • obtuse • acute • right angle • obtuse
straight angle straight angle • an angle • whose measure is • 180 degrees
straightangles • not straight angles
Page 28 number 1 - 10 • measure of angle ARF 180 degrees straight angle • measure of angle CRF 120 degrees obtuse 3. measure of angle BRF 155 degrees obtuse
adjacent angles adjacent angle • two angles • have same vertex • share one ray
List adjacent angles • Adjacent angles
List adjacent angles • Adjacent angles
adjacent angles • not adjacent angles
Page 29 • 1.Angle CDB is adjacent to angle _____ • 2. Angle TUV is adjacent to angle ____ • 3. Angle SRP is adjacent to angle ____
vertical angles Vertical angles • When two lines intersect • two pairs of vertical angles are formed
vertical angles Vertical angles are NOT adjacent. Vertical angles have the same measure.
Page 30 Vertical angles 1. angle YPV and angle ____ • angle YPV and angle RPS • angle QPR and angle _____ • angle QPR and angle VPT
complementary angles • two angles • sum of measures • is 90 degrees
complementary angles What angles are complementary? Why?
complementary angles Are these angles complementary? Why or Why not?
complementary angles • not complementary angles
Supplementary angles • two angles • sum of measures • is 180 degrees
Supplementary angles • two angles • sum of measures • is 180 degrees
Why are figure 1 and figure 2 both examples of supplementary angles?
supplementary angles • not supplementaryangles