Dr. black is standing 13 feet from a street lamp. the lamp is making his shadow 9 feet long. he estimates that the angle of elevation from the tip of his shadow to the top of the street lamp is 50 degrees. to the nearest door, the street lamp is about

To clarify your question, the last part. Is it to the nearest foot or door? If you meant door then your answer is:

13 + 9 = 22 feet
the angle is 50 degrees
multiply 22 x tan(50) to find the height of the lamppost
22 x tan(50) = 26.21 so the lamppost is about 26 feet tall

The answer is part a: use

The answer is 41.7 because 1.39 times 30 is 41.7