GRE Math Problem 13

Given:

Compare two values:

Column A	Column B
(a+b)2	(a-b)2

Solution for GRE Math Problem 12:

The sum of those two angles of quadrilateral is 2x60=120^o. Since the sum of all four angles of quadrilateral is 360^o, the sum of other two angles is 360-120=240^o and their average is 240/2=120. So, the columns are equal.
Answer:C

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