If you have a quadrilateral whose angles measure 90, 90, 60, 120 where the right angles are opposite each other does that mean that the quadrilateral is tangential. If it is can somebody show me how they arrived at that conclusion?
The quad with angles 90°, 60°, 90°, 120° is obviously symmetric
Are you sure about that?
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There must be some other condition for the OP's statement to be true. Four angles do not fix the shape of a quadrilateral. In the diagram, you can draw any lines parallel to the sides and get different shaped quadrilaterals with the same angles. They can't all be tangential quadrilaterals.