<span>Rectangles have a couple of properties that help distinguish them from other parallelograms. By studying these properties, we will be able to differentiate between various types of parallelograms and classify them more specifically. Keep in mind that all of the figures in this section share properties of parallelograms. That is, they all have</span>
The slope formula is slope = y2 - y1 / x2 - x1 and the variables are found by assigning them with their corresponding values. Here, x1 = -9, x2 = -13, y1 = 18, and y2 = 5. Next, substitute these values in and get 5 - 18 / -13 - (-9). This can fully simplify to 13 / 4 or 3.25.