Coterminal angles are any two angles that have the same starting and ending points regardless of the measurement
Keep adding 360 until you get to a positive number
-613+360 =-253
-253+360=207
The coterminal angle is 107
This is in quadrant II
To find the reference angle, we want to get to the axis as fast as possible
The negative x axis is faster
180-107 = 73
The reference angle is 73 degrees