<PRE><B>Question 1025987</B>
We have parallelogram ABCD with interior angles a, b, c, d
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Use law of cosines to find angle b with AC = 28
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28^2 =  22^2 + 12^2 - (2*22*12)cos(b)
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cos(b) = &amp;#8722;0.295454545
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cos^(-1) (&amp;#8722;0.295454545) = 107.184795874
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angle b is approx 107.2 degrees
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therefore,
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angle c is 72.8 because angle b and angle c are supplementary 
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angle d = angle b because alternate angles are congruent
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angle c = angle a becuase alternate angles are congruent
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each diagonal partitions the parallelogram into congruent triangles
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note that unless the parallelogram is a rhombus, the diagonals do not bisect the interior angles
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