# Is my answer correct?

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Thread starter 1 week ago
#21
I am very confused right now
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1 week ago
#22
(Original post by Kakakaty)
I am very confused right now
How have you been taught to calculate a gradient?
Via the equation of the line, trigonometry etc...?
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1 week ago
#23
(Original post by mqb2766)
Not sure what you mean?
It looks very similar to how you can calculate the slopes (i.e tan thetas) in the original problem
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1 week ago
#24
(Original post by Kakakaty)
I am very confused right now
Get the gradient of each line first. How do you calculate them - see the maths is fun link.
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Thread starter 1 week ago
#25
(Original post by Always_Confused)
How have you been taught to calculate a gradient?
Via the equation of the line, trigonometry etc...?
The change in Y divided by change in X
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1 week ago
#26
(Original post by Kakakaty)
for A i got 3 and for B i got 2.5
I know that their gradients will multiply together to give -1 but from the gradient I got they don't equal -1 so does that mean theyre not perpendicular or did i do my calculations wrong?
Your calculations are wrong. From the answers you have given though, I suspect for A you have made a division error and B you have subtracted something incorrectly. If you would like to PM me a photo of your working out I can tell you where you've gone wrong
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Thread starter 1 week ago
#27
(Original post by mqb2766)
Get the gradient of each line first. How do you calculate them - see the maths is fun link.
I have done this, I got A=3 B=2.5. I followed the steps on the website are my answers incorrect?
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1 week ago
#28
(Original post by Kakakaty)
The change in Y divided by change in X
(Original post by Kakakaty)
I have done this, I got A=3 B=2.5. I followed the steps on the website are my answers incorrect?
Yes for the third time. What is the change in y and the change in x?
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1 week ago
#29
(Original post by Kakakaty)
I have done this, I got A=3 B=2.5. I followed the steps on the website are my answers
Line A: two points on the line are 1: (3, 5) and 2: (6,6). x2 - x1 = 6 - 3 = 3. y2 - y1 = 6 - 5 = 1.
Gradient = (y2 - y1)/(x2 - x1) = 1/3
Do the same thing for two points on line B.

Do the gradients multiply to -1?
If yes: lines are perpendicular
If no: lines are not perpendicular
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Thread starter 1 week ago
#30
This is an image of what I did so for line A I have the y value (2) and the x value (6) 2/6 = 0.3. and then for line B I have the y value of 5 and the x value of 2. 5/2 = 2.5. Where am I going wrong?
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1 week ago
#31
(Original post by Kakakaty)
This is an image of what I did so for line A I have the y value (2) and the x value (6) 2/6 = 0.3. and then for line B I have the y value of 5 and the x value of 2. 5/2 = 2.5. Where am I going wrong?
Line A is now correct 0.333... Line B goes down, so what does that mean for the gradient (change in y)?
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Thread starter 1 week ago
#32
(Original post by mqb2766)
Line A is now correct 0.333... Line B goes down, so what does that mean for the gradient (change in y)?
-2.5 ?
1
1 week ago
#33
(Original post by Kakakaty)
-2.5 ?
Yes
So their product is ?
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Thread starter 1 week ago
#34
(Original post by mqb2766)
Yes
So their product is ?
-0.75 ?
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1 week ago
#35
(Original post by Kakakaty)
-0.75 ?
Well it's -5/6 without the rounding.
It's close to -1 but not quite equal.
The lines are almost perpendicular (eyeballing them) but not quite when you do the numbers.
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Thread starter 1 week ago
#36
(Original post by mqb2766)
Well it's -5/6 without the rounding.
It's close to -1 but not quite equal.
The lines are almost perpendicular (eyeballing them) but not quite when you do the numbers.
Woooo thankyou for you help.
One last thing
Would this be ok for my final answer -

The lines A and B would not be perpendicular this is because in order for them to be perpendicular their gradients must multiply together to get -1. Line A's gradient is 0.333.... and Line B's gradient is -2.5. When multiplying these together you get -5/6 (0.83333...). Therefore, this means they are not perpendicular as they do not multiply together to get -1.
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1 week ago
#37
(Original post by Kakakaty)
Woooo thankyou for you help.
One last thing
Would this be ok for my final answer -

The lines A and B would not be perpendicular this is because in order for them to be perpendicular their gradients must multiply together to get -1. Line A's gradient is 0.333.... and Line B's gradient is -2.5. When multiplying these together you get -5/6 (0.83333...). Therefore, this means they are not perpendicular as they do not multiply together to get -1.
Fine, but I'd really recommend you do some more practice on the line / gradient basics.
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Thread starter 1 week ago
#38
(Original post by mqb2766)
Fine, but I'd really recommend you do some more practice on the line / gradient basics.
I agree, I really need to, It seems the information never stays in my brain. I've tried finding resources online of where I can practice linear graphs, gradients etc but I can't find many resources which have ways to practice.
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1 week ago
#39
(Original post by Kakakaty)
I agree, I really need to, It seems the information never stays in my brain. I've tried finding resources online of where I can practice linear graphs, gradients etc but I can't find many resources which have ways to practice.
drfrostmaths.com
you can get questions about all parts of the syllabus graded 1-4, including this topic.
Tbh, most gcse maths sites will have questions about this. Just have a look at the usual suspects, after trying drfrostmaths.
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Thread starter 1 week ago
#40
(Original post by mqb2766)
drfrostmaths.com
you can get questions about all parts of the syllabus graded 1-4, including this topic.
Tbh, most gcse maths sites will have questions about this. Just have a look at the usual suspects, after trying drfrostmaths.
Thankyou !
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