Yes, it’s all trigonometry. I’m not going to try to write you a trig class specifically for US², but I can at least state that it can be done. You need knowledge of right triangles, in other words Sine, Cosine, Tangent, and the Pythagorean theorem. Luckily, you don’t know to use spherical trig. That is however needed to give moons’ orbits a specific tilt to a planet’s equatorial plane.