Question

what is the diference between radians and degrees

Answer 1

Radians refers to the circle in terms of pi, whereas degrees refers to a circle in terms of... degrees. There are (in the example of a circle) 360 degrees and 2pi (or 2 radians)

Answer 2

90 degrees = pi/2 (because they are each a quarter of a circle)

Answer 3

there are 2* pi radians in a circle and 360 degrees
2pi radians is equivalent to 360 degrees

a radian is formed when you trace a length of the radius along the curve of the circle