The radius of the circle in the picture provided is one unit. Express the lengths OA, AB, and DC in terms of x.
Have you made any effort to solve this? What are the coordinates of point $\displaystyle C~?$
What are the coordinates of point $\displaystyle B~?$
What are the coordinates of point $\displaystyle D~?$
Thank you, Plato. I will work on this more on my next day off, which is Monday. This question is from a chapter titled Right-Triangle Trigonometry. A very cool topic.