math
posted by sarah .
A storage tank has a radius of x + 5 metres and a height of x metres. Determine the dimensions of the tank if the volume is 192ð m3? . Round your answers to two decimal places.

V = pi r^2 h
= pi (x+5)^2 x = pi (x^2 +10 x +25)x
= pi (x^3 + 10 x^2 + 25 x
= 1920 ????
if so then
x^3 + 10 x^2 + 25 x  611.15 = 0
find roots:
http://www.mathportal.org/calculators/polynomialssolvers/polynomialrootscalculator.php
Only real root is at x = 5.52
then r = 10.52
and h = 5.52