HELP, GIVING BRAINLIEST TO THE BEST ANSWER. Ruth decides to use the method of proportions and similar triangles to find the height of a tree. She measures the length of the tree's shadow and finds it is 12 feet long. Then she holds a 12-inch ruler perpendicular to the ground and finds that it casts a 6-inch shadow. How tall is the tree? a. 2 ft c. 24 ft b. 6 ft d. 144 ft