At a point 4 feet from the driveway the height of the ramp is 12 inches. at 6 feet from the driveway, the height of the ramp is 18 inches. what is the rate of change of the ramps incline

The figure shows triangle def and line segment bc, which is parallel to ef: triangle def has a point b on side de and point c on side df. the line bc is parallel to the line ef. part a: is triangle def similar to triangle dbc? explain using what you know about triangle similarity. part b: which line segment on triangle dbc corresponds to line segment ef? explain your answer. part c: which angle on triangle dbc corresponds to angle f? explain your answer. asap