Mercury's average distance from the earth is approximately 57,000,000 km. Earth's distance to the Sun is approximately 150,000,000 km. What is the distance between the Sun and Mercury?

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?