First lets get the formula for a triangular prism

First lets plug in our numbers

It really doesnt matter how you multiply everything, but you end up with 119cubic feet.
Answer:
Step-by-step explanation:
The continuous compound formula is
where P is the principle or starting value, r is the growth rate in decimal form, and t is the time in years. For us:

which would probably round to just 3848 people.
The volume of the pyramid is 15 yd
For me personally, the easiest way to do this is by isolating the x² term, and finding the square root of both sides. The hardest way (well actually, the longest way) would be to use the quadratic formula. It just complicates things unnecessarily.