Final answer:
The volume of a cylindrical tank is found using the formula V = πr²h. To find the radius r, the formula can be rearranged to r = √(V/(20π)). For a tank with a radius of 12 feet, the volume V is approximately 9,048 cubic feet without extraneous solutions.
Step-by-step explanation:
The volume V of a cylindrical tank is calculated using the formula V = πr²h. To find the radius r, we can rearrange the formula to r = √(×/(πh)). Therefore, given h = 20 feet, the formula becomes r = √(×/(20π)), which simplifies to r = √(V/(20π)). As for the graph, it will show r on the y-axis and V on the x-axis, and will represent the positive branch of a parabola since √(V) is being plotted.
If the tank's radius is 12 feet, using the formula V = π(12²)(20), we find V to be approximately 9,048 cubic feet. Since the calculation is based on an actual measurement for the radius, there are no extraneous solutions.