Thanks to all of you who support me on Patreon. You da real mvps! $1 per month helps!! 🙂 https://www.patreon.com/patrickjmt !! Related Rates #8 – Cars Traveling from an Intersection – Rate of Change in Perimeter of Triangle Formed. In this example, two cars start at the same intersection with one traveling north and one traveling east. We find the rate in change of the perimeter of the triangle formed by the two cars and the intersection.