No, it is not possible to print 100 digits after the decimal in Progress. But honestly, why would you?
If you don't need to do that specific calculations you can always use a CHARACTER field.
From the F1-help:
DECIMAL
DECIMAL data consists of decimal numbers up to 50 digits in length including up to 10 digits to the right of the decimal point.
INTEGER
An INTEGER consists of 32-bit data (whole numbers).
(Integer must be between -2147483648 and 2147483647).
INT64
An INT64 consists of 64-bit data (whole numbers).
(INT64 must be between -9223372036854775808 and 9223372036854775807)
Note that these are absolute limits and has nothing to do with the display format of the variable/field/widget. Display format (FORMAT statement) only affects the possibility to display and can be even more limiting (but can also be overridden programmatically).