Question

What is the reference angle for 225° and what is a reference angle?

Answer 1

if i can remember correctly the reference angle is:
Given angle - 180
so that reference angle would be 45 deg

Answer 2

reference angle = angle in first quadrant
here it is 225-180 = 45 degrees

Answer 3

oh and it should be positive http://www.mathwarehouse.com/trigonometry/reference-angle/finding-reference-angle.php