How do you prove algebraically, that the following vertices are a rectangle. I can plot it on a graph, but I can't figure out how to prove using algebra.

Help.

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- January 10th 2010, 07:08 AMGR9STUDENTProving quadrilateral is a rectangle algebraically
How do you prove algebraically, that the following vertices are a rectangle. I can plot it on a graph, but I can't figure out how to prove using algebra.

Help. - January 10th 2010, 07:32 AMVonNemo19
- January 10th 2010, 07:34 AMGR9STUDENT
Sorry, I did not list the vertices, they are (1,0) (-1,5) (4,7)(6,2)

- January 10th 2010, 07:57 AMVonNemo19
1 way to do it:

Let the given points correspond to respectively.

Then to show that is a rectangle, we must show that each interior angle measures . To do this, we must need to only compare the slopes of line segments with , and with and etc...

Do you get what I'm saying? - January 10th 2010, 08:12 AMGR9STUDENT
No, I am lost on this one.

I understand that the rectangle has four 90 angles, and that the slope of each pair of lines will equal each other. But I don't know how to show with forumula. - January 10th 2010, 08:24 AMVonNemo19
- January 10th 2010, 08:49 AMGR9STUDENT
Thankyou, that makes sense.