The cost, in dollars, of producing x jackets is given by . find the rate at which the average cost is changing when 484 jackets have been produced. find the rate at which the average cost is changing when 484 jackets have been produced. dollars per jacket (round to four decimal places as needed.)

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