00:05
So we want to compare angles that are measured in radiance with angles that are measured in degrees.
00:19
Shown here is a straight angle.
00:23
The measure of this angle in degrees is 180 degrees.
00:31
The measure of this same angle in radiance is pi.
00:39
Radiance.
00:49
So 180 degree angle is equal to an angle that measures pi radiance.
00:56
We're talking about the same straight angle here.
00:58
In degrees, this is 180 degrees.
01:01
In radiance, this is pi radiance.
01:05
Now, if 180 degrees is equal to pi radiance, how many degrees would one radian be? so if we have one radian, then we want to convert.
01:24
One radian into degree measurement.
01:29
We have an angle that measures one radian.
01:34
One radian to turn it into degrees, we are going to multiply this by 180 degrees over pi radiance.
01:51
Since 180 degrees is the same angle as an angle that measures pi radians, this is the conversion factor that we're going to use.
02:03
180 degrees equals pi radiance.
02:10
What happens is to convert the one radian into an angle measured in degrees, we take the one radian, we times it by 180 degrees over pi radians.
02:21
These are equivalent.
02:23
And what happens is radiance is going to cancel.
02:27
So we're going to lose that unit of measurement.
02:30
What's going to be left is degrees.
02:32
So we have 1 times 180 degrees over just a number pi.
02:41
We don't have radians anymore...