Question

The maximum load that a cylindrical column with a circular cross section

can hold varies directly as the fourth power of the diameter and
inversely as the square of the height. A 9 meter column 2 meters in
diameter will support 64 metric tons. How many metric tons can be
supported by a column 9 meters high and 3 meters in diameter?

Answer 1

2396

Explanation:

Let the diameter = d

Let the height = h

Formula

Metric Tons = k * d^4 / h^2

Solution

Metric Tons = 64

d = 2

h = 9

k = ?

(You can't do the second part by not using a ratio unless you put k in and solve for it)

64 = 2^4 k / 9^2

64 = 8 *k / 81

64 * 81 / 8 = k

5184 / 8 = k

k = 648

Solve for the second example

Metric Tons = d^4 * k / h^2

Metric Tons = ?

d = 5

h = 13

k = 648

Metric Tons = 5^4 * 648 / 13^2

Metric Tons = 625 * 648 / 169

Metric Tons = 2396 rounded.