# How do I change from Radians to Degrees and vice versa?

• Mar 30th 2009, 02:10 PM
Polyxendi
How do I change from Radians to Degrees and vice versa?
I was sick and absent from school for the last few days and this is one of the topics that will come on the test on Thursday.

Any help would be greatly appreciated!
• Mar 30th 2009, 02:41 PM
masters
Quote:

Originally Posted by Polyxendi
I was sick and absent from school for the last few days and this is one of the topics that will come on the test on Thursday.

Any help would be greatly appreciated!

Hi Polyxedni,

To change from degrees to radians, multiply degrees by $\frac{\pi}{180}$

Example: Change 30 degrees to radians

$30^{\circ}\cdot \frac{\pi}{180}=\frac{30 \pi}{180}=\frac{\pi}{6}$ radians.

To change from radians to degrees, multiply radians by $\frac{180}{\pi}$

Example: Change $\frac{\pi}{2}$ radians to degrees

$\frac{\pi}{2} \cdot \frac{180}{\pi}=90^{\circ}$
• Mar 30th 2009, 02:42 PM
Ian1779
Well there are $2\pi$ radians in 360 degrees.

Use the expression: $2\pi/360$.

Then you can convert back and forth.

Example - how many radians in 90 degrees?

$radians = 2\pi*(degrees)/360$

How many degrees in 2 radians?

$degrees = (radians)*360/2\pi$

Hope this helps :)
• Mar 30th 2009, 04:02 PM
Polyxendi
Thank you!!