McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
6. Trapezoids and Kites
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Exercise 60 Page 529

Recall the classification of quadrilaterals. You can begin by finding the slopes of the sides.

Parallelogram

Practice makes perfect

Let's plot the given points on a coordinate plane and graph the quadrilateral.

To determine the most precise name for our quadrilateral, let's review the classification of quadrilaterals.
Quadrilateral Definition
Parallelogram Both pairs of opposite sides are parallel
Rhombus Parallelogram with four congruent sides
Square Parallelogram with four congruent sides and four right angles
Trapezoid Quadrilateral with exactly one pair of parallel sides

Let's first find the side's slopes using the Slope Formula.

Side Slope Formula Simplified
Slope of AB: ( - 1,4), ( 2,6) 6- 4/2-( - 1) 2/3
Slope of BC: ( 2,6), ( 3, 3) 3- 6/3- 2 - 3
Slope of CD: ( 3,3), ( 0,1) 1- 3/0- 3 2/3
Slope of DA: ( 0,1), ( - 1,4) 4- 1/- 1- 0 - 3

We can tell that the slopes of the opposite sides of our quadrilateral are equal. Therefore, both pairs of opposite sides are parallel and the quadrilateral is therefore a parallelogram. We can also tell that the consecutive side are not perpendicular, as their slopes are not opposite reciprocals. - 3 (2/3) ≠ -1 Therefore, our quadrilateral is either a parallelogram or a rhombus. To check, we can find the lengths of its sides using the Distance Formula.

Side Distance Formula Simplified
Length of AB: ( - 1,4), ( 2,6) sqrt(( 2-( - 1))^2+( 6- 4)^2) sqrt(13)
Length of BC: ( 2,6), ( 3,3) sqrt(( 3- 2)^2+( 3- 6)^2) sqrt(10)
Length of CD: ( 3,3), ( 0,1) sqrt(( 0- 3)^2+( 1- 3)^2) sqrt(13)
Length of DA: ( 0,1), ( - 1,4) sqrt(( - 1- 0)^2+( 4- 1)^2) sqrt(10)

Our parallelogram has two pairs of congruent sides. Therefore, the most specific term for this quadrilateral is a parallelogram.