Go Math Chapter: 11 Angles

right angle

an angle that forms a square corner and has a measure of 90 degrees

obtuse angle

an angle that measures greater than 90 degrees and less than 180 degrees

acute angle

an angle that measures less than 90 degrees and greater than 0 degrees

ray

part of a line that has one end point, and continues without end in one direction

90 degrees

right angle measurement

180 degrees

straight angle

vertex

the point at which two rays on an angle meet or two (or more) line segments meet in a two 2D shape.

360 degrees

the total measure of degrees in a circle

3/4 turn

270 degrees around a circle

5 min on a clock or 1/12 of a circle

30 degrees

whole turn

360 degrees around a circle

1/4 turn

90 degrees around a circle

protractor

A tool used for measuring the size of an angle

counterclockwise

In the opposite direction in which the hands of a clock move

clockwise

In the same direction in which the hands of a clock move

degree

The unit used for measuring angles

1/360 of a circle

1 degree

1/2 turn

180 degrees around a circle