Find triangle rectangle opposite side length

Question

In the right-angled triangle below, is it possible to find length $BC$ with only length $AC$ and angle $A$?

Answer 1

You know Angle A and side length AC therefore to find side length BC you can use trigonometry.

$\tan\theta = \frac O A$
$\tan A = \frac{BC}{AC}$
$BC=\tan A\times AC$