Finding length of isosceles triangle

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I have the following homework question: find the length of side h. Assume the largest triangle is isosceles.
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The way I'm thinking about it is that the 2 same angles could be any of the following options:
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The answer is assuming that the 2 angles in Option A are the same, h=5.66.
I don't understand why Option B and Option C cannot be viable options? Why can't the 2 angles in either Option B or Option C be the same?

Thank you

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Let the marked angle be $a$.

The other cases would imply $\frac{a}{2} + a + 90º = 180º$, or that $a = 60º$. This would mean that the triangle is equilateral. However, one of the sides is $2 + 2 = 4$, and one of the sides is $6$, so the triangle is not equilateral – a contradiction.

Therefore, the marked angles are the ones in the first case.