Question

The points D, left parenthesis, 9, comma, minus, 4, right parenthesis, comma, E, left parenthesis, 6, comma, 8, right parenthesis, comma, F, of, minus, 3, comma, 6D(9,−4),E(6,8),F(−3,6), and G, of, 0, comma, minus, 6G(0,−6) form quadrilateral DEFG. Plot the points then click the "Graph Quadrilateral" button., On this question page, you will first graph points on a coordinate grid. Following the graph are two buttons, "Graph Quadrilateral" will drawn lines between your points, and "Reset" will remove all of your points. Once you press Graph Quadrilateral, if your points are correct, the answer area will appear.
Click on the graph to plot a point. Click a point to delete it.
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y
D
E
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Use the dropdown menus and answer blanks below to prove the quadrilateral is a parallelogram.
Answer
Attempt 1 out of 2

I will prove that quadrilateral DEFG is a parallelogram by demonstrating that

Answer 1

I will prove that quadrilateral DEFG is a parallelogram by demonstrating that both pairs of opposite sides are parallel.

Compute slopes:
- slope DE = (8 − (−4)) / (6 − 9) = 12 / (−3) = −4
- slope FG = (−6 − 6) / (0 − (−3)) = −12 / 3 = −4
Thus DE ∥ FG.

- slope EF = (6 − 8) / (−3 − 6) = (−2) / (−9) = 2/9
- slope DG = (−6 − (−4)) / (0 − 9) = (−2) / (−9) = 2/9
Thus EF ∥ DG.

Since both pairs of opposite sides are parallel, DEFG is a parallelogram.