Rotational :is a angle that from the 0 line

Reference : is the angle that always close to the middle linelike this

Coterminal angle: is a angle that always negative and is a angle that are shared same arm with the rotational.

example:rotational angle is 243 degree

so reference is 243-180=63 degree

and we use the way

look at this picture:

so we use this graph to solve

The angle in quadrant 1 :63 degree

The angle in quadrant 2: 180-63=117degree

The angle in quadrant 3 :180+63=243degree

The angle in quadrant 4:360-63=297degree

because we already know the reference angle

so it is very easy to solve

And we also learned the angles with triangle

an isosceles right triangle and an acute right triangle

remember we know the triangle in 4 different quadrant

use the formula y/r , x/r , y/x

and use the way that Mrs. Burton taught

“All Student Take Calculus”

In the quadrant 1 the sin,cos,tan are all positive

in quadrant 2 just sin is the positive

in quadrant 3 just tan is the positive

in quadrant 4 just cos is the positive

so it is a good way to solve the degree

for example:sin 135 degree

we use the picture we find this is a 45 degree triangle

so we use o/H (y/r)=1/√2=√2/2

Thank you for reading