Answer:
900%
Step-by-step explanation:

The volume of pyramid A is 384 cubic inches.
3456/384 = 9
Pyramid B's volume is 900% bigger than pyramid A's volume.
Circumference= diameter x pi
12x3.14 = 37.68
<h2>
Change of the distance between the observer and the airplane when X = 5 miles is 348.84 mph</h2>
Step-by-step explanation:
We have by Pythagoras theorem
Distance between the observer and the airplane² = Horizontal distance² + Altitude²
d² = h² + a²
Here we have
h = X = 5 miles
a = 7 miles
d² = 5² + 7² = 74
d =8.60 miles

Differentiating d² = h² + a² with respect to time

Change of the distance between the observer and the airplane when X = 5 miles is 348.84 mph