Consider the absolute value, because we only worry about the quadrant later.


Thus, we know that the hypotenuse has a length of 4 units, and the side opposite the angle, A is √3, because this is the nature of the sine function in relation to its triangular component.
The missing side can be found using Pythagoras' Theorem:
4² - (√3)² = x²
16 - 3 = x²
13 = x²
x = √13

Since angle A is in the third quadrant, the tangent function will produce a positive angle.


