Question 1191691
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ST and AR are opposite sides of the parallelogram STAR.


They are congruent and have equal lengths.  So

    ST = AR,  or  2x + 5 = 16.


It implies  

    2x = 16 - 5 = 11.

     x          = 11/2 = 6.5.    <U>ANSWER</U>
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Solved.