A power plant has 4 tons of coal. A ton produces 2,460 kilowatt hours of electricity. The Plant reserves enough electricity to power nine light bulbs for a year. How many additional kilowatt hours of electricity are produced? (876 kilowatt of electricity to power a 100-watt light bulb a year)

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?