# Math Help - how to do this one with trigonometry

1. ## how to do this one with trigonometry

A cylindrical storage tank has a radius of 5m and a height of 18m. A staircase allowing access from the ground to the top of the tank circles the tank once. Determine the angle of inclination of staircase to the nearest degree.

2. Originally Posted by davedave
A cylindrical storage tank has a radius of 5m and a height of 18m. A staircase allowing access from the ground to the top of the tank circles the tank once. Determine the angle of inclination of staircase to the nearest degree.
Immagine cutting the tank long ways and rolling it out flat.

The length of the bottom is the circumference of the tank $C=2\pi (5)=10\pi$

The height is 18. So now the angle we want is

$\alpha =\tan^{-1}\left( \frac{18}{10\pi}\right) \approx 29.8^\circ$