Determine whether poss. to have triangle w/ given vertices

rubyred

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1. Determine whether it is possible to have atraingle with vertices A(1, -1), B(7,7) C(2,-5) Write Yes or No and Explain your answer.

How would i prove this? I need help to start it out, thanks!
 
Re: Detrmine traingle verticies help asap!

1. Determine whether it is possible to have atraingle with vertices A(1, -1), B(7,7) C(2,-5) Write Yes or No and Explain your answer.

Simply plot the three points on a graph and connect the points. You get a triangle.

In general, any three points that are not colinear (on the same line) define a plane -- and a triangle.

To demonstrate algebraically that the points are not colinear, simply calculate the slopes between all the points. If they are all different, then they are not on the same line.
 
Re: Detrmine traingle verticies help asap!

Hello, rubyred!

1. Determine whether it is possible to have a triangle with vertices A(1,-1), B(7,7) C(2,-5).
Write Yes or No and Explain your answer.

Three points always determine a triangle ... unless the points are collinear.

\(\displaystyle \text{Examine the slopes: }\:\begin{array}{ccccccc}m_{_{AB}} &=& \frac{7-(\text{-}1)}{7-1} &=& \frac{4}{3} \\ \\[-3mm] m_{_{AC}} &=& \frac{-5-(\text{-}1)}{2-1} &=& -4 \end{array}\qquad\text{The points are }not\text{ collinear.}\)


. . \(\displaystyle \text{Therefore, points }A,B,C\text{ form a triangle.}\)

 
I just graphed the points and they form a traingle but then when the questions says
Write yes or no and expalin
I just said Yes, because it makes a triangle.
Is this correct?
 
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