Why is the data type of PI not specified

Question

After the #define there is no data type for PI, why is that

Answer 1

Assuming the language is C or C++ (Please add the language in the keywords!)

#define is handled by the pre-processor, not the compiler.
And PI is a placeholder, not a typed C variable.

The pre-processor is just replacing all occurrences of the string PI in the source code with the defined value (as a replacement string)

then the compiler compiles the resulting processed source code.