Always to do each to 1 sigfig 20-6=14
16/2 times 2 =16, 2/2 times 16 = 16
We know that
[volume of a sphere]=(4/3)*pi*r³
length of a circumference=42 ft
[length of a circumference]=2*pi*r-------> r=[length of a circumference]/(2*pi)
r=[42]/(2*pi)---------> r=6.6845 ft
[volume of a sphere]=(4/3)*pi*6.6845³-----------> 1251.11 ft³
the answer is 1251.11 ft³
Answer: A reasonable estimate of the minimum is 20.
ANSWER
A parabola.
EXPLANATION
The given conic is :

This can be rewritten as:


This is a parabola with the vertex at the origin.
The foci is (0,4)
Therefore the given conic section is a parabola that has an axis of symmetry parallel to the y-axis.