When it is necessary to verify observer-target distance, the flash to bang technique can be used. To estimate the distance of the impact of your artillery, or sound from the enemy explosions, etc., you must count from the flash to sound you hear. How many meters per second are used to estimate that distance?

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