Televisions are advertised by the length of the diagonals a store is having a sale of 10% off of all television smaller than 40 inch and 20% off for 40inch or larger what is the the price for model b

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?