7. Polygons in the Coordinate Plane
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Find the slopes of the sides of the parallelogram.
Rhombus
Let's plot the given points on a coordinate plane and graph the parallelogram.
Parallelogram | Definition |
---|---|
Rhombus | Parallelogram with four congruent sides |
Rectangle | Parallelogram with four right angles |
Square | Parallelogram with four congruent sides and four right angles |
Now, we will find the slopes of the sides using the Slope Formula.
Side | Points | y_2-y_1/x_2-x_1 | Simplify |
---|---|---|---|
LM | L( 1,2), M( 3,3) | 3- 2/3- 1 | 1/2 |
MN | M( 3,3), N( 5, 2) | 2- 3/5- 3 | 1/2 |
NP | N( 5, 2), P( 3, 1) | 1- 2/3- 5 | 1/2 |
PL | P( 3, 1), L( 1,2) | 2- 1/1- 3 | 1/2 |
We can tell that the consecutive sides are not perpendicular, as their slopes are not opposite reciprocals. 1/2 * 1/2 ≠- 1 Since rectangles and squares have perpendicular sides, our parallelogram can only be a rhombus or none of the given types of parallelograms. To check if it is a rhombus, we can find the lengths of its sides using the Distance Formula.
Side | Points | sqrt((x_2-x_1)^2+(y_2-y_1)^2) | Simplify |
---|---|---|---|
LM | L( 1,2), M( 3,3) | sqrt(( 3- 1)^2+( 3- 2)^2) | sqrt(5) |
MN | M( 3,3), N( 5, 2) | sqrt(( 5- 3)^2+( 2- 3)^2) | sqrt(5) |
NP | N( 5, 2), P( 3, 1) | sqrt(( 3- 5)^2+( 1- 2)^2) | sqrt(5) |
PL | P( 3, 1), L( 1,2) | sqrt(( 1- 3)^2+( 2- 1)^2) | sqrt(5) |
Our parallelogram has four congruent sides, that are not perpendicular. Therefore, the most precise name for this parallelogram is rhombus.