Standard Position, Coterminal and Reference Angles

standard position

- an angle is in standard postion if its vertex is located at the origin and one ray is on the positive x-axis.

Counterclockwise angle measurement

the measurement of the angle is positive

coterminal angles

two angles that have the same terminal side.

Quadrantal angle

- if the terminal side of an angle lies on the axis (like a 90 or 180 degree angle).

initial side

- the ray on the x-axis of an angle in standard position.

terminal side

- the ray that rotates in an angle in standard position.

260 degrees

Find an angle coterminal to -100 degrees

-250 degrees

Find an angle coterminal to 110 degrees

-200 degrees

Find an angle coterminal to 160 degrees

440 degrees

Find an angle coterminal to 80 degrees

80 degrees

Find the reference angle of 100 degrees

30 degrees

Find the reference angle of 210 degrees

60 degrees

Find the reference angle of 300 degrees

reference angle

an acute angle formed by the terminal side of the given angle and the x-axis.

clockwise angle measurement

the measurement of the angle is negative