How to use letters to represent two digits or more

How to use letters to represent two digits or more


Draw an up line on ABCD



A two digit number, the number of ten is a, and the number of one is B. the two digit number is ()


The two digits in letters are: 10A + B



A multiplied by a and then multiplied by a is 4000,
The original problem is to cut a cube with a volume of 4000 cubic centimeters into the largest cylinder to calculate the volume of the cylinder,


A times a and a times a is 4000
a³=4000
A = 4000 under the third root
a≈15.874010519681994747517056392723