7.3 Angles and their measures

Definitions Angle-A geometric figure consisting of 2 rays

with a common endpoint Vertex-The common endpoint of rays Ray-Side of an angle Measure of an angle-The side of an angle;

measured in degrees Protractor-Tool used to measure angles Right angle-90 degree angle

More Definitions Acute angle-An angle less than 90 degrees

but greater than 0 Obtuse angle-Angle greater that 90 degrees

but less than 180 degrees Straight angle-180 degree angle

Ex 1:

Name

A

B

C

BAC

CAB

l

A

Vertex always has to be in the middle

Ex. 2:

What are the restrictions on X if < A is acute

( 2x+8)

A

< A can be <90 and > 0

2x+8 <90 and 2x +8>0-8 -8

2x > -8

2 2

-8 -8

2x < 822 2

x > -4

X < 41 and x > -4