Help if possible thank you :)

Empty box + box + empty box fill in the box is equal to 30 how

1yd 1 ft = 1 1/12 1 1/3 1 1/2 1 1/6

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