Question 1144561
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Let x be the side length of this equilateral triangle, in inches.


Then the length of the side of the square is  (x-4) inches, according to the condition.


Then the condition on perimeters gives you this equation


    3x = 4(x-4) + 3.


Simplify and solve


    3x = 4x - 16 + 3

    3x = 4x - 13

    13 = 4x - 3x

    13  = x.          <U>ANSWER</U>
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