McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
5. Rhombi and Squares
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Exercise 21 Page 518

Recall the classification of quadrilaterals. Begin by finding the slopes of the sides of the quadrilateral.

Type of Parallelogram: Parallelogram, none of the mentioned.
Explanation: See solution.

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 parallelogram, let's review the classification of parallelograms.
Quadrilateral Definition
Rhombus Parallelogram with four congruent sides
Rectangle Parallelogram with four right angles
Square Parallelogram with four congruent sides and four right angles

Now, let's find the slopes of the sides using the Slope Formula.

Side Points y_2-y_1/x_2-x_1 Simplify
JM ( - 2,- 1), ( 3,1) 1-( - 1)/3-( - 2) 2/5
ML ( 3,1), ( 1,5) 5- 1/1- 3 - 2
LK ( 1,5), ( - 4, 3) 3- 5/- 4- 1 2/5
KJ ( - 4, 3), ( - 2,-1) - 1- 3/- 2-( - 4) - 2

We can tell that consecutive sides are not perpendicular, as their slopes are not opposite reciprocals. - 2(2/5 ) ≠ -1 Therefore, our quadrilateral is either a parallelogram or a rhombus. To check this, we can find the lengths of its sides using the Distance Formula.

Side Points d = sqrt((x_2-x_1)^2 + (y_2-y_1)^2) Simplify
JM ( - 2,- 1), ( 3,1) sqrt(( 3-( - 2))^2+( 1-( -1))^2) sqrt(29)
ML ( 3,1), ( 1,5) sqrt(( 1- 3)^2+( 5- 1)^2) 2sqrt(5)
LK ( 1,5), ( - 4, 3) sqrt(( - 4- 1)^2+( 3- 5)^2) sqrt(29)
KJ ( - 4, 3), ( - 2,-1) sqrt(( - 2-( - 4))^2+( - 1- 3)^2) 2sqrt(5)

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