Answer:
Mean is 84
Step-by-step explanation:
PLEASE HELP FAST!!! ILL MARK B.
You can eliminate 81 because we know 
The dot is on approximately 9.32 (my estimate) so I would square that number:
(9.32)² = 86.8624 so if you round this you get 87
Check the picture below.
now, the "x" is a constant, the rocket is going up, so "y" is changing and so is the angle, but "x" is always just 15 feet from the observer. That matters because the derivative of a constant is zero.
now, those are the values when the rocket is 30 feet up above.

Answer:
3.14159265358979323846264338327950288419716... thats all i know, but i havent studied it in a while