Video Transcript
What is the equivalent measure of 360 degrees in radians?
We know that an angle of 360 degrees represents one full revolution. So the question then becomes โwhat is the measure of one full revolution in radians?โ To do this, we use the definition of the measure of an angle in radians. Itโs equal to the length of the intercepted arc divided by the radius of the circle. So this ๐ that weโre trying to find the measure of is the angle in the diagram. And we want to apply our formula to this angle.
Letโs start with the radius. Weโre not told what the radius is in the question. And so we assume it can take any value. And so we can call this value ๐. So now weโve decided what to call the radius, we can move on to the arc length. This is the length of the arc intercepted by the angle.
And as the angle is one full revolution, the arc intercepted is the entire circumference of the circle. And we know what the circumference of the circle is in terms of our radius ๐; itโs just two ๐๐.
Now that we found that the arc length is two ๐๐ and the radius is ๐, we can simplify. We cancel the ๐s and weโre left with just two ๐. So the equivalent measure of 360 degrees in radians is two ๐ radians.
