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# C1 question- coordinate geometry watch

1. Hi,

For question 6, I've done parts a-c, but how would you do 6(d)?
The answer is (11,6) as the coordinates of d.
https://f9732c7b8f9d5d47d6a3db1be3fd...%20Edexcel.pdf

Thank you
2. (Original post by Shanahey)
...
Since this is a rectangle AD = BC.

Since you know C from part c), you can work out BC, and hence AD. And since you know A,....
3. (Original post by ghostwalker)
Since this is a rectangle AD = BC.

Since you know C from part c), you can work out BC, and hence AD. And since you know A,....
Sorry please could you clarify further?? How would you use the length AD to find the coordinates of d?
4. (Original post by Shanahey)
Sorry please could you clarify further?? How would you use the length AD to find the coordinates of d?
It's not the length of AD, but rather the difference in x-coordinates of A and D, and the difference in y-coordinates of A and D,

The difference in coordinates of A and D, is the same as B and C.
5. Since you now know the coordinates of C (8,10) I believe? And since it's a rectangle the lines Ab and DC are parallel and equal in length. To get from B to A you add 3 to the x coordinate and subtract 4 from the y. And so doing the same thing with C you get D as (8+3,10-4) = (11,6)
6. (Original post by ghostwalker)
It's not the length of AD, but rather the difference in x-coordinates of A and D, and the difference in y-coordinates of A and D,

The difference in coordinates of A and D, is the same as B and C.
Thank you!

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