To determine what part of 72 is 36a, we need to divide 72 by 36a. This will give us the ratio of 72 to 36a, which is equal to the part of 72 that is represented by 36a.
The result of this division is 72 / 36a = 2 / a. This means that 36a is equal to 2/a parts of 72.
For example, if a = 1, then 36a = 36, and 36 is equal to 2/1 parts of 72, or 2 parts. This means that 36 is equal to 2/1 * 72 = 144, which is equal to 2 parts of 72.
If a = 2, then 36a = 72, and 72 is equal to 2/2 parts of 72, or 1 part. This means that 72 is equal to 1 part of 72.
In general, the value of 36a will depend on the value of a. The value of 36a will be larger if a is smaller, and it will be smaller if a is larger.