The Pythagorean theorem should help you out. Since you already know two sides of the triangle, you can do a^2 + b^2 = c^2
So in this problem, 16.5^2 + 9.2^2 = 272.25 + 84.64 = 356.89
Pasty you would take the square root of 356.89 and you would get x = 18.89 or 18.9 rounded to the nearest tenth
You can check your work by the Pythagorean theorem once more. 16.5^2 + 9.2^2 = 18.9^2 and you should get the same approximate answer (it will be a little bigger because you rounded)
The volume of rectangular prism = length x height x width so sub in the above equation we get 840 = length x 6 x 10 length = 840 /(60 x 10) length = 14 inches
