Sine: demonstrative model
Objective
We have seen in the illustrative model that the sine value () of a right triangle (green) depends only on the value of angle . Why is that so?
This result can be proven using Thales Theorem: just remember what Thales Theorem states.
In the following dynamic model, you can move orange points (slope-point, A, B and C).
You can use the "control box" to superimpose the green triangle you have been using until now on top of the geometrical structure (Thales Theorem).