McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
4. Rectangles
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Exercise 17 Page 508

The diagonals of a rectangle are congruent.

ZX=38

Practice makes perfect

Let's analyze the given quadrilateral WXYZ to find the length ZX. We are told that the figure is a rectangle.

First, by the Segment Addition Postulate, we can express the length of each diagonal as the sum of lengths of its smaller segments. ZX= ZP+PX and WY=WP+PY

Additionally, because a rectangle is a parallelogram, we know that the diagonals bisect each other. This means that point P divides each diagonal into halves. ZP= PX and WP= PY We can use this fact to rewrite the Segment Addition Postulate equations in terms of the given expressions, ZP= 4x-9 and PY= 2x+5.

Equation ZX=ZP+PX WY=WP+PY
Substitution ZX=ZP+ ZP WY= PY+PY
Simplification ZX=2ZP WY=2PY
Substitution ZX=2( 4x-9) WY=2( 2x+5)
Now, recall that the diagonals of a rectangle are congruent. Therefore, their lengths are equal. ZX=WY ⇔ 2(4x-9)=2(2x+5) We can use this equation to solve for x.
2(4x-9)=2(2x+5)
â–Ľ
Solve for x
4x-9=2x+5
4x=2x+14
2x=14
x=7
Now that we know the value of x, we can find ZX using the equation from the table.
ZX=2(4x-9)
ZX=2(4( 7)-9)
â–Ľ
Evaluate right-hand side
ZX=2(28-9)
ZX=2(19)
ZX=38
We found that the length of ZX is 38.