A block is not a uniform unit of measure. The two units are therefore incompatible.
1
52800 x 12...
Divide the inches by 12.
0.0833 feet.
There are 12 inches in a foot. 1 inch = 0.08333 feet
5.15 feets
three feets
12 feet.
10 to 12 blocks
61/(12 x 2.54) is a whisker over 2 feet.
Divide by 12.
12 blocks is a mile