Answer:
Pythagorean theorem, eh?
Step-by-step explanation:
The way to do this is use the radius-tangent angle theorem thing...
It states that, a radius that intersects a point of tangency(I think that's what it's called) is perpendicular to the tangent. Thus, CW is perpendicular to OW!
Thus, it forms a right triangle, where we can use Pythagorean Theorem!
If you don't know what it is, check the internet! It's pretty simple.
So, there you go! Hope this helps!
NOTE: This answer was recently deleted for violating community guidelines, so I just re-uploaded it!(and edited it) So if you do need more help, do some research!