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Recall the theorem, which tells us that if a quadrilateral is a parallelogram then its opposite sides are congruent.
x=2
y=7
We want to find the values of x and y for which the given quadrilateral is a parallelogram, using the given algebraic expressions for the lengths of the half-diagonals.
Recall the following theorem.
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Converse Parallelogram Diagonals Theorem |
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If the diagonals of a quadrilateral bisect each other, then the quadrilateral is a parallelogram. |
Therefore, for the quadrilateral to be a parallelogram, the segments with the following lengths are congruent. 4y-9 = 2y+5 and y+3 = 2x+6 Let's create a system of equations by substituting the lengths of the segments into these equations. 4y-9=2y+5 y+3=2x+6 To solve it we will use the Substitution Method.
(I): LHS-3=RHS-3
(I): y= 2x+3
(I): Multiply
(I): Add and subtract terms
(I): LHS-3=RHS-3
(I): LHS-4x=RHS-4x
(I): .LHS /4.=.RHS /4.
Now that we have found x, we can substitute it in the second equation to find y.
(II): x= 2
(II): Multiply
(II): Add terms