Pearson Geometry Common Core, 2011
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Pearson Geometry Common Core, 2011 View details
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Exercise 16 Page 425

Recall the theorem which tells us that if a quadrilateral is a parallelogram, then its opposite sides are congruent.

x=2
y=1

Practice makes perfect

We want to determine the values for which ABCD is a parallelogram, using the given algebraic expressions for the segment lengths.

Recall the theorem which tells us that if a quadrilateral is a parallelogram, then its opposite sides are congruent. Therefore, the following segments are congruent. AB ≅ DC and AD ≅ BC By the definition of congruent segments, we can conclude that their lengths are equal. AB=DC and AD=BC Let's create a system of equations by substituting the lengths of the segments into these equations. 7x-2=5x+2 6x+y=7x-1 To solve it we will use the Substitution Method.
7x-2=5x+2 & (I) 6x+y=7x-1 & (II)
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(I): Solve for x
2x-2=2 6x+y=7x-1
2x=4 6x+y=7x-1
x=2 6x+y=7x-1
Now that we have found x, we can substitute it into the second equation to find y.
x=2 6x+y=7x-1
x=2 6( 2)+y=7( 2)-1
x=2 12+y=14-1
x=2 12+y=13
x=2 y=1