Measure the height and radius of the tank. The radius is the distance from the center of the tank to its outer edge. Another way to find the radius is to divide the diameter, or width, by two. Square the radius by multiplying the radius times itself and then multiply it by 3.1416, which is the constant pi.
Given height and volume: r = √(V / (π * h)),
Given height and lateral area: r = A_l / (2 * π * h),
Given height and total area: r = (√(h² + 2 * A / π) - h) / 2,
Given height and diagonal: r = √(h² + d²) / 2,
Given height and surface-area-to-volume ratio: r = 2 * h / (h * SA:V - 2),
Given volume and lateral area: r = 2 * V / A_l,
Given base area: r = √(A_b / (2 * π)),
Given lateral area and total area: r = √((A - A_l) / (2 * π)).
