Find the mean of these job salaries

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?

Factor the polynomial by its greatest common monomial factor.

What rotation was applied to triangle def to create d’e’f’?