Core 1 help please! Watch

luke5675
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Question: I have found out 3 co-ordinates of a triangle (0,0), (0,-7) and (3,-6) from previous questions, now I am asked to find the area of this triangle. How is this possible if I don't know the height and all the lengths are different?

Thanks in advance!
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TenOfThem
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(Original post by luke5675)
Question: I have found out 3 co-ordinates of a triangle (0,0), (0,-7) and (3,-6) from previous questions, now I am asked to find the area of this triangle. How is this possible if I don't know the height and all the lengths are different?

Thanks in advance!
You do know both the base and the height

I suggest that you sketch a diagram and all should become clear
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luke5675
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Yes, sketch looks like right angled, but line (0,0) to (0,-7) is not perpendicular to the line (0-7) to (3,-6)? So this means that the height is not -7 as it is not a right angled triangle?
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TenOfThem
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(Original post by luke5675)
Yes, sketch looks like right angled, but line (0,0) to (0,-7) is not perpendicular to the line (0-7) to (3,-6)? So this means that the height is not -7 as it is not a right angled triangle?
It is not right angled but you have a base that is on one of the axes and therefore know the height
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luke5675
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Sorry about this, still slightly confused as would that not be the slanted height of triangle?
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TenOfThem
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(Original post by luke5675)
Sorry about this, still slightly confused as would that not be the slanted height of triangle?
I am not sure what you are looking at

Having drawn the triangle you should have a base (on the y-axis) and 2 slanting sides

Draw the height in - you should be able to see instantly how tall the triangle is
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THEMathlete
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Use pythagoras to find the distance between the points

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TenOfThem
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(Original post by THEMathlete)
Use pythagoras to find the distance between the points

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Why

That will not help to solve this problem at all
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luke5675
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Sorry it took quite a while to see this, understand what you are saying now though. Thanks for your help!
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TenOfThem
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(Original post by luke5675)
Sorry it took quite a while to see this, understand what you are saying now though. Thanks for your help!


In C1 - all questions of this sort will have 2 co-ordinates that form the base then you you just need to draw in the height
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techno-thriller
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Find the lengths between the points

I.E distance= (x1-x2)^2+(y1-y2)^2 do for all sides the put each number on their respective side and use 1\2height x base
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TenOfThem
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(Original post by techno-thriller)
Find the lengths between the points

I.E distance= (x1-x2)^2+(y1-y2)^2 do for all sides the put each number on their respective side and use 1\2heightxbase
This is nonsense - in no way does it help to solve the problem given
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techno-thriller
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(Original post by TenOfThem)
This is nonsense - in no way does it help to solve the problem given
:confused:

I was just doing a problem like this.
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Jatom
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Triangle doesn't have to be right-angled If the co-ordinates you gave are correct, then the area is 10.5 squared units
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Jatom
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don't know why it's upside down! haha
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TerribleTej
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the base is seven and height is 3, and that can be derived from the question itself once you draw out the triangle on a graph. then your answer will be 0.5*base*height
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TenOfThem
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(Original post by techno-thriller)
:confused:

I was just doing a problem like this.
incorrectly, I assume

there is no need for Pythagoras in this question
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luke5675
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Didn't expect so many responses to my first post! Thanks a lot for all of your feedback
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TenOfThem
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(Original post by luke5675)
Didn't expect so many responses to my first post! Thanks a lot for all of your feedback
Welcome to maths
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BWV1007
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Honestly... I think you can just use the formula

Area of triangle =
| x1 x2 x3 x1 |
| y1 y2 y3 y1 |

= 1/2[(x1 x y2) + (x2 x y3) + (x3 x y1) - (y1 x x2) - (y2 x x3) - (y3 x x1)]
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