For any parallelogram, the opposite angles are always congruent. The upper left corner shows angle W = 75 degrees. The angle opposite this is angle Y in the bottom right corner, so angle Y must also be 75 degrees.
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The opposite sides of a parallelogram are parallel. Because WX is parallel to VY, this means the alternate interior angles WXV and YVX are the same measure. The diagram shows angle WXV = 39. Therefore, angle YVX is also 39 degrees.
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The opposite sides of a parallelogram are also the same length (in addition to being parallel). The opposite sides WV = 3x and XY = 12 are the same length, meaning....
