To find the volume of a cylindrical tank, we can use the formula for the volume of a cylinder:
\[ V = \pi r^2 h \]
where:
- \( V \) is the volume,
- \( r \) is the radius of the cylinder,
- \( h \) is the height (or length) of the cylinder.
In this problem:
- The radius \( r = 5 \) feet,
- The height \( h = 36 \) feet.
Now we can plug in the values:
\[ V = \pi (5^2)(36) \]
Calculating \( 5^2 \):
\[ 5^2 = 25 \]
Now substituting this back into the volume equation:
\[ V = \pi (25)(36) \]
Calculating \( 25 \times 36 \):
\[ 25 \times 36 = 900 \]
Thus, the volume of the tank is:
\[ V = 900\pi \]
Therefore, the amount of fuel inside the tank is:
\[ \boxed{900\pi} \]