7ab+5 is the simplest it can be
ANSWER

EXPLANATION
According to the power property of logarithms:

The given logarithm is

When we apply the power property to this logarithm, we get,

Isosceles Triangle, has 2 equal sides and angles.
The answer to your question is 81,300.
It's not an irrational number because the decimal is repeating. If it went on forever and never repeated then it would be an irrational number.
I think the error is that Richie thought for a number to be irrational, it just needed to repeat forever.