To determine the depth of the water, let's use the Pythagorean Theorem.
[tex]x=\sqrt{c^2-a^2}[/tex]
where c = the length of the hypotenuse and a = length of one of the legs.
Since c = 15 ft and a = 6 ft, let's plug them into the formula above.
[tex]x=\sqrt{(15ft)^2-(6ft)^2}[/tex]
Then, solve.
[tex]x=\sqrt{225ft^2-36ft^2}[/tex][tex]x=\sqrt{189ft^2}[/tex]
Get the square root of 189 using a calculator.
[tex]x=13.7477ft\approx13.7ft[/tex]
Therefore, the water is approximately 13.7 feet deep.
