C. N. Coln Geometry St. Barnabas HS Bronx, NY Rays and Angles
Ch. 1.5 and 1.6
Slide 3
A RAY consists of a point on a line and all points on one side
of the point. K A D This ray can be called AK or AD The beginning
of the name is the endpoint, A.
Slide 4
Opposite rays are two rays of the same line with a common
endpoint and no other points in common RAY CC TT A
Slide 5
Oh, Mrs. C, you are tooooooo funny!
Slide 6
This is an angle
Slide 7
A n angle is a set of points that is the union of two rays
having the same endpoint A n Side Vertex DD EE There are several
ways to name this angle: A DAE EAD n
Slide 8
In this case there is no confusion you name an angle by the
vertex. A A
Slide 9
obtuse angle acute angle
Slide 10
Slide 11
A B C D How many angles do you see? A 1 B 2 C 3 D Huh?
Slide 12
Degrees were developed by the Babylonians thousands of years
ago. They divided a circle into 360 parts and called each part one
degree.
Slide 13
The symbol for degrees, as you probably already know, is a
small superscript circle. 4537112
Slide 14
Slide 15
This is an acute angle and it measures 61
Slide 16
This is an obtuse angle and it measures 127
Slide 17
A: 180B: 125C: 50D: 25
Slide 18
Angles are congruent if they have the same measure. A B
Slide 19
If point S is in the interior (middle) of angle PQR, then the
measure of PQS + measure of SQR = measure of PQR P Q R S
Slide 20
P Q R S The bisector of an angle is a ray whose endpoint is the
vertex of the angle, and that divides the angle into two congruent
angles. PQS = SQR ~
Slide 21
Complementary angles are two angles that total 90 degrees 30
and ___ 27 and ___ 12 and ___ 63 60 78
Slide 22
Supplementary angles are two angles that total 180 degrees 25
and ___ 67 and ___ 124 and ___ 155 56 113
Straight angle is an angle that is the union of opposite rays.
It makes a straight line and measures 180
Slide 35
Linear angles are two angles that share a side and make a line.
We also called them supplementary angles Linear angles total
180
Slide 36
Right angles are angles that measure 90
Slide 37
Acute angles measure less than 90
Slide 38
Obtuse angles are angles that measure more than 90 but less
than 180
Slide 39
Perpendicular lines are lines that intersect to form right
angles. The shortest distance from any point to a line is the
length of the perpendicular from the point to the line.
Slide 40
A reflex angle is an angle that measures more than 180
