The vertex of an isosceles triangle is 9 degree more than a base angle. find the vertex angle? !

You can use the Pythagorean Theorem to obtain the altitude (the unknown side in the middle.)The vertex, B, is split into two equal angles, but you can easily find the vertex angle by first finding one of the base angles.

Try doing what Lashia answered, if not, please comment on this answer for further help. :)

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