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Need help with a simple maths question

When I get 3 co-ordinates A(6,-2) B(4,1) and C(-2,-3)


and am asked to find the area of the triangle ABC, i draw the triangle on the axis and I have to work out the length of the line of 2 of the side but my problem is i don't know which lines...... like how do I know which one is the base then both BC and AC look like they could be the base.

thx
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Zacken
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Original post by jeja12
When I get 3 co-ordinates A(6,-2) B(4,1) and C(-2,-3)


and am asked to find the area of the triangle ABC, i draw the triangle on the axis and I have to work out the length of the line of 2 of the side but my problem is i don't know which lines...... like how do I know which one is the base then both BC and AC look like they could be the base.

thx


You can take either of them to be the base, you'll get the same answer.
Reply 2
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jeja12
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Original post by Zacken
You can take either of them to be the base, you'll get the same answer.


Well when I do height as AB I get root13 and base as BC I get root 52
when I work it out I get the area to be 13 (correct)


but when I use AC as the base i get root 65 and when I work it out I get 13root5/2
Reply 3
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Zacken
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Original post by jeja12
Well when I do height as AB I get root13 and base as BC I get root 52
when I work it out I get the area to be 13 (correct)


but when I use AC as the base i get root 65 and when I work it out I get 13root5/2


If you use AC as the base, the height is not going to be AB anymore, the height will be something else...
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jeja12
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Original post by Zacken
If you use AC as the base, the height is not going to be AB anymore, the height will be something else...


What would be the height if I use AC then and how do I know every time which lengths to use for height and which to use for the base? thx and sorry for being stupid ;p
Reply 5
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Zacken
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Original post by jeja12
What would be the height if I use AC then and how do I know every time which lengths to use for height and which to use for the base? thx and sorry for being stupid ;p


The sketch should show what the height will be if you use one side as the base. It's the perpendicular distance from the base to the third vertex.
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jeja12
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Original post by Zacken
The sketch should show what the height will be if you use one side as the base. It's the perpendicular distance from the base to the third vertex.


Im not sure what you mean by the perpendicular distance from the base to the third vertex, do you know of any video explaining this? I can't seem to find anything
Reply 7
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Zacken
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Original post by jeja12
Im not sure what you mean by the perpendicular distance from the base to the third vertex, do you know of any video explaining this? I can't seem to find anything


Reply 8
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jeja12
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So in this case the height would be AB since it's the shortest length and then I would draw a line down from B making AC the base?

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