If you haven’t seen the video on angles in standard position and the reference angle, or you are not clear on these concepts, it is recommended going here first: https://mathpqjq.com/angles-in-standard-position-and-the-reference-angle/

If we are given a point on the terminal arm of an angle in standard position, we will see how all trigonometric ratios can be determined. 

If we are given a ratio in fractional form, we will see how this information will allow us to find all trigonometric ratios.

We will also discuss how to find exact ratios for the angles in special triangles.

The video on special triangle ratios can be found here: https://mathpqjq.com/special-triangle-ratios/