Download Angles in Standard Position

Lesson 2 – Radian Measure and Angles on the Cartesian Plane
STANDARD POSITION
An angle is in standard position when
its vertex is at the origin (0,0) and the
initial arm lies on the POSITIVE x-axis.
The angle measure
the origin.
indicates the amount of rotation of the terminal arm about


counterclockwise rotation
(+) angle measure
clockwise rotation
(-) angle measure
Coterminal angles are angles which
share the SAME terminal arm.
The related acute angle is the acute
angle between the terminal arm and
the x-axis.
 = 1200
SPECIAL TRIANGLES IN RADIANS
CAST


Cast rule is an easy way to remember which primary
Trigonometric ratios are positive in which quadrant
Since r is always positive, the sign of each primary
trig ratio depends on the signs of the coordinate point.
I
II
III
S
A
T
C
IV
Examples
1.
Determine the exact value of each trigonometric ratio:
a)
b)
c)
2.
If
, where
, determine the exact value of .
3.
If
, where
, evaluate  to the nearest hundredth.