Post on 22-Feb-2016
description
Angles
Angles A shape formed by two rays sharing a
common endpoint; contains two rays and a vertex
ray
ray
vertexray—has one endpoint and goes infinitely in one direction
vertex—point common to two rays of a triangle or two sides of a polygon
Naming AnglesAn angle is named by three letters.
The vertex must be in center.
A
B C
1
Types of Angles Acute angle: An angle whose
measure is greater than zero degrees and less than 90 degrees
Which angles are not acute?1
23
4
5
Types of Angles Right angle: Angle that measures
90 degrees
Which angle is a right angle?1
23
4
5
Types of Angles Obtuse angle: One angle measures
greater than 90 degrees and less than 180 degrees
Which angle is an obtuse angle?1
23
4
5
Straight Angle Straight angle: A line that goes
infinitely in both directions and measures 180 degrees
Which is not a straight angle?
1 2
This is a ray. It only goes in one direction.
Adjacent angles are “side by side” and share a common ray.
45º15º
These are examples of adjacent angles.
55º
35º
50º130º
80º 45º
85º20º
These angles are NOT adjacent.
45º55º
50º100º
35º
35º
When 2 lines intersect, they make vertical angles.
75º
75º
105º105º
Vertical angles are opposite one another.
75º
75º
105º105º
Vertical angles are opposite one another.
75º
75º
105º105º
Vertical angles are congruent (equal).
30º150º
150º30º
Supplementary angles add up to 180º.
60º120º
40º
140º
Adjacent and Supplementary Angles
Supplementary Anglesbut not Adjacent
Complementary angles add up to 90º.
60º
30º40º
50º
Adjacent and Complementary Angles
Complementary Anglesbut not Adjacent
Practice Time!
Directions: Identify each pair of angles as vertical, supplementary, complementary, or none of the above.
#1
60º120º
#1
60º120º
Supplementary Angles
#2
75º75º
#2
75º75º
Vertical Angles
#3
65º
25º
#3
65º
25º
Complementary Angles
Directions:Determine the missing angle.
#1
45º?
#1
45º135º
#2
65º
?
#2
65º
25º
#3
35º
?
#3
35º
35º
#4
50º
?
#4
50º
130º