100*36 - (2*36) = 3600 - 72 = 3528.
This question does not make sense.
With just 1/(3x) you can't isolate it; however, 1/(3x) = 1/3 * (1/x).
1 km cubed = 0.239912759 miles cubed
So 100 km cubed would be 23.99 or 24 miles cubed.
arc cos or acos(-0.517) = ~ 121 degrees.