A tree makes a shadow that is 14 ft long. Colleen is 6ft tall. When she is standing near the tree, her shadow is 3.5 ft long. How tall is the tree?

This is a ratio set up, and we will put the shadow height on the top of the fractions and the height of the objects on the bottom: 14/x = 3.5/6. We can use cross-multiplication to do the solving: 3.5x = 84 and x = 24. So the tree is 24 ft tall