A tanker truck has overturned and is spilling oil onto the highway. Amazingly, the region covered by the oil spill maintains a perfectly circular shape. The area covered by the spill is growing at a rate of 40π square feet per minute. How quickly is the radius of the oil spill growing when it covers an area of 100π square feet?

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