4222.3 is the volume of the cylinder. If you want me to explain step-by-step just comment.
$1 - (28,996/29,000) = 0.000138
0.0138%
You have to move the decimal point two places to the left to convert a percent to a decimal, so the answer is 0.925.
You need to divide 25.4 and 4 and you'll get 6.35