Pythagoras: Get b when only a and angle α are given

Question

Given the Pythagoras Theorem: a² + b² = c²

Is there a way to get the value of b when we only have a value for a and the angle α?

To be frank, I have no clue about that, what I want isn't the angle of β but the length of b (Opposite).

Answer 1

$$a = b\tan\theta$$

Where $\theta$ is the angle opposite to $a$

From this:

$$b = \frac{a}{\tan\theta}$$

Answer 2

Pythagoras Theorem is a theorem about right-angle triangles so if we know one of the angles (except $90^{\circ}$, which is not the case in here), then we know all of the angles and knowing one of the sides of the triangle is enough for finding other two.