It’s mid-afternoon on a lovely, sunny day; it’s 60°F, and the sun is 60° above the horizon. Rays from the sun strike the still surface of a shallow pond that is 20 cm deep. The rays of sun cast a shadow of a stick that is completely submerged, and stuck in the sandy bottom of the pond. If 10 cm of the stick is above the sand, what is the length of the shadow?