To find the height of this tree, Luis marked the tree at eye level, 1.8 meters above the ground. He measured 32 m from the base of the tree and then held a 5-cm ruler vertically in front of his eye until the ruler just obscured the tree above the mark. Using a string tied through a hole in one end of the ruler, Luis found that the distance from his eye to the ruler was 4.7 centimeters. What was the height of the tree?