If the point is at (-3, -4), it is located in the third quadrant. You can find the tangent of an angle by finding the ratio of the length of the opposite side to the length of the adjacent side. In this case, the opposite side of the angle is the vertical line with a length of 4 units, while the adjacent side of the angle is the horizontal line with a length of 3 units. Thus, tan θ = 4/3.