Peter Breuer

The method you have proposed for solving this is an algebraic approach and would be valid only when AH/EH = ... (see the picture).

On the other hand, I suggest resolving this geometrically.

Peter Breuer

There is an inaccuracy in your formula, and it will only be valid under a specific ratio as shown in the photo below. In all other cases, unfortunately, it is incorrect.

Peter Breuer

You are looking for the ratio AH/EH – that's correct!

There was an error in your formula; the correct formula is as follows:

2/(1-tg^2(ABC/2)).

You need to use the formula for the tangent of a double angle:

tg(ABC) = (2tg(ABC/2))/(1-tg^2(ABC/2))

Peter Breuer

Now your response is perfect!

Thank you for your interest and perseverance!