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Recall the classification of quadrilaterals. You can begin by finding the slopes of the sides.
Parallelogram
Let's plot the given points on a coordinate plane and graph the quadrilateral.
Let's review the classification of quadrilaterals.
Quadrilateral | Definition |
---|---|
Parallelogram | Both pairs of opposite sides are parallel |
Rhombus | Parallelogram with four congruent sides |
Rectangle | Parallelogram with four right angles |
Square | Parallelogram with four congruent sides and four right angles |
Trapezoid | Quadrilateral with exactly one pair of parallel sides |
Isosceles Trapezoid | Trapezoid with legs that are congruent |
Kite | Quadrilateral with two pairs of consecutive sides congruent and no opposite sides congruent |
Now, let's find the slopes of the sides using the Slope Formula.
Side | Slope Formula | Simplified |
---|---|---|
Slope of AR: ( - 2,12), ( 5,8) | 8- 12/5-( - 2) | - 4/7 |
Slope of RG: ( 5,8), ( 2, 5) | 5- 8/2- 5 | 1 |
Slope of GD: ( 2,5), ( -5,9) | 9- 5/- 5- 2 | - 4/7 |
Slope of DA: ( -5,9), ( - 2,12) | 12- 9/- 2-( - 5) | 1 |
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 a parallelogram. Let's multiply the slopes of two consecutive sides 1 ( - 4/7 ) = - 4/7 Since the product is - 47≠- 1 the sides are not opposite reciprocals. Therefore, the 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 AR: ( - 2,12), ( 5,8) | sqrt(( 5-( -2 ))^2+( 8- 12)^2) | sqrt(65) |
Length of RG: ( 5,8), ( 2, 5) | sqrt(( 2- 5)^2+( 5- 8)^2) | sqrt(18) |
Length of GD: ( 2,5), ( -5,9) | sqrt(( - 5- 2)^2+( 9- 5)^2) | sqrt(65) |
Length of DA: ( -5,9), ( - 2,12) | sqrt(( - 2-( - 5))^2+( 12- 9)^2) | sqrt(18) |
Our quadrilateral has two pairs of congruent sides. Therefore, the most precise name for it is a parallelogram.