Answer:
45
Step-by-step explanation:
Start by setting the function equal to 0 and then moving the -5.4 over to the other side of the equals sign.

. The first rule for completing the square is that the leading coefficient be a +1. Ours is a -.2. So we need to factor it out.

. Now we will take half the linear term, square it, and add it to both sides. Our linear term is 14. Half of 14 is 7, and 7 squared is 49. So we add 49 in to the left side just fine, but we cannot forget about that -.2 hanging around out front as a multiplier. What we have actually "added" in is -.2*49 which is -9.8. Now here's what we have after all that:

. In that process, we have created a perfect square binomial on the left. Along with expressing that binomial we will do the math on the right:

. Now we will move the -4.4 back over by addition, and it will then be apparent as to what our vertex is. The y coordinate of the vertex will give us the max height of the water.

. As you can see, our work matches choice C from above.
10 x 10 = 100 80 x 80 =6400 6400-100= 6300 so that would have to be 3150ft.
I wish i could show u how to work it out but just do it or work it out the same way as the fractional numbers.
To find midpoint, we find the average or median of the two x terms and the average of the two y terms to find the right coordinate point. In this case, the average of -2 and 6 is 2, and the mean of 4 and -4 is 0, so the new coordinate point is (2,0).