Points, Lines, and Angles Chapter 2 Points, Lines, and Angles
Goal Tell type of angle. Label angles. Measure angles.
Review
A? B? C? a ) ray b) line segment c) line
Check a ) ray b) line segment c) line
Review all
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
Unit of measurement is degrees
List everything you can tell about this angle.
-Angle – 2 rays that intersect -Sides – rays - Point where rays intersect – vertex - Angle ABC or CBA -Measured in degrees - 60 degrees
Types of Angles
Right Angle Right angle an angle whose measure is 90 degrees
right angles orientation – direction still right angle
right angles not right angles
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? examples of obtuse Obtuse angle
Obtuse Angles Not Obtuse
What type of angle? Why? Check again
Why type of angle? A? B? C? D? E? F? acute right angle obtuse
acute right angle obtuse
straight angle straight angle an angle whose measure is 180 degrees
straight angles 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.
Which angles are vertical?
Which angles are adjacent?
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
a and b angles are complementary even when not connected complementary = sum of angles equals 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? Review 1 obtuse angle 2 acute angle 1 and 2 supplementary
supplementary angles not supplementary angles
Review of Angles
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