Radian and Degree Measure

Trigonometry: The measurement of triangles with the relationship among sides and angles.

Angles: 2 rays with a common end point (vertex)

The angle is measured by the amount of rotation from the initial side to the terminal side. If measured in a counterclockwise direction the measurement is positive and if it is measured in a clockwise direction the measurement is negative.

If two angles in standard position have the same terminal side, then they are called coterminal angles.

Two positive angles  A and B are complementary if their sum is:

Two positive angles A and B are supplementary if their sum is:

Converting Degrees to Radians:

Example:

The radian measure formula can be used to measure arc length along a circle

Example:

 

First convert 115 degrees to radiant

Next plug in information in to the radian measure formula

Estimate your answer