At a marathon there is loud music at a water station to cheer the runners on. The marathon route turns a right-angled corner 200m past the water station. The runner's speed is 4m/s. How fast is the distance between the runner and the water station increasing when the runner is 100m past the corner?
Im pretty sure I have to use the Pythagoras theorem, to solve, but I cant figure out how to set it up properly. Any help would be greatly appreciated. If possible show all steps to getting the answer. Thanks again!