# Thread: Geometry Marathon

1. Please, show a picture.

(for better understanding)

2. I attached the image in the previous post.

3. brilliant! bravo! don't you just love triangles?!
shoot us with a question!

4. Here is the problem:

5. Originally Posted by Krizalid
This problem looks like hard, but it's not when you find a good auxiliary construction.

Another solution
• Take a point $E$ on the extension of $\overline{AC}$ such that $\overline{BA}=\overline{BE}\implies\measuredangle~ CBE=x~\therefore~\triangle{BAC}\cong\triangle{BED}$.
• Finally $\measuredangle~BDE=4x\implies{x}=18^\circ~\blacksq uare$

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