Please help me I will give out the brain thing and extra credit, but please hurry up.

Two similar shaped buildings both cast a shadow. The shadows were measured, and their dimensions are shown. If the height of Building B is 120 ft., what is the height of Building A? Show your work and don’t forget to add the units to your answer.

Afarmer has a large field that is x feet in length. he wants to fence in a rectangular section in the middle of the field , leaving a length of 100 feet of open field behind each end of the fenced rectangle. he also wants the width of the fenced-in space to be 100 feet less than its length. find the expressions to represent the length and width of the fenced section of the field