Abuilding across the street casts a shadow that is 24 feet long. your friend is 6 feet tall and casts a shadow that is 4 feet long. what is the height of the building?

Set it up as a proportion. start with the smaller numbers, 6 ft friend and 4 ft shadow. 4/6 reduces to 2/3.  so 2/3= 24/x.   the easiest way to finish the problem is to divide by 2, and multiply by 3. for instance- 24/2= 12. 12*3= 36, so the building is 36 feet tall. to check plug it back in, is 2/3= 24/36?