Radian Measure
How to change angle in degree measure to radian measure and vice versa: definition, formula, 2 examples, and their solutions.
Definition
Definition
Radian is another way
to write the measure of an angle.
Remember this definition:
π radian = 180 degrees.
Formula
Formula
To find radian measure from degree measure,
multiply [π/180].
Example 1
Example
Solution
The given angle is in degree measure:
30 degrees.
To change this to radian measure,
multiply [π/180].
Cancel the numerator 30
and reduce the denominator 180 to, 180/30, 6.
Then you get π/6.
So 30 degrees is π/6 radian.
You don't have to write the radian unit [rad].
So π/6 is the answer.
Example 2
Example
Solution
The given angle is in radian measure:
π/4.
Set the degree measure θ.
Then θ⋅[π/180] = π/4.
Divide both sides by [π/180].
Then θ = [π/4]⋅[180/π].
Cancel π factors.
Cancel the denominator 4
and reduce the numerator 180 to, 180/4, 45.
So the right side is 45.
So π/4 radian is 45 degrees.