How do I find the reference angle of A) 1.3 B) 5 Please explain

The reference angle refers to the angle in quadrant I, with the same triangular ratios. Measure how far the angle is from the x axis.

So in radians, The quadrants are separated by 0,pi/2, pi, 3pi/2 in decimal form as shown:

................1.57
3.14-------|-------0
................4.71

A) 1.3 is in quadrant I, so the reference angle is 1.3

B) 5 rads is in quadrant IV, between 4.71 and 2pi= 6.28
the size of the angle is 6.28 -5= 1.28
The reference angle is 1.28 rads

Hoping this helps!