Atree makes a shadow that is 14 ft long. rachel is 6 ft tall. when she id standing near the tree, her shadow is 3.5 ft long. which statement best explain why rachel can use a proportion to estimate the length of the tree?

The triangle that is formed from by connecting the shadow, the tree and the endpoints of each is a right triangle. The two triangles formed (by the tree and its shadow, and by Rachel and her shadow) are similar. In similar triangles, the corresponding sides are proportional. Thus, to give the numerical answer to this item,
                         length  of the tree/14 ft = 6 ft / 3.5 ft
                                  length of the tree = 24 ft