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Circle Question

Can someone check my answers:

For A i got (3,-1)

then for B i got (x-3)^2 +(y+1)^2 = 15

then for c this is the one I'm not very sure about i got 5root 5
Circle questions.docx39.2KB
Original post by Hollymae764
Can someone check my answers:

For A i got (3,-1)

then for B i got (x-3)^2 +(y+1)^2 = 15

then for c this is the one I'm not very sure about i got 5root 5

can someone help me with the last one d because I don't understand how to do it. thank youu
Reply 2
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mqb2766
21
Original post by Hollymae764
Can someone check my answers:

For A i got (3,-1)

then for B i got (x-3)^2 +(y+1)^2 = 15

then for c this is the one I'm not very sure about i got 5root 5

For b) have you checked it by subbing in a point? There is a small mistake.
Original post by mqb2766
For b) have you checked it by subbing in a point? There is a small mistake.

Should the 15 be 15^2
Reply 4
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mqb2766
21
Original post by Hollymae764
can someone help me with the last one d because I don't understand how to do it. thank youu

C is right.
For D) you need to find RQ using pythagoras, then it's just simple trig.
Reply 5
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mqb2766
21
Original post by Hollymae764
Should the 15 be 15^2

Yes, just put in one of the points to check if you're not sure.
Original post by mqb2766
C is right.
For D) you need to find RQ using pythagoras, then it's just simple trig.

Im confused, how do i used Pythagoras if the triangles not right angled
Reply 7
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mqb2766
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Original post by Hollymae764
Im confused, how do i used Pythagoras if the triangles not right angled

PQR is right angled (thales circle theorem).
I got the answer 41.8 is this correct
Reply 9
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mqb2766
21
Original post by Hollymae764
I got the answer 41.8 is this correct

Looks about right, but it helps to see your working if possible (next time)?
Original post by Hollymae764
I got the answer 41.8 is this correct

A slightly different way would be to find angle PAR then half of that (exterior angle to an isosceles triangle). It would save calculating QR. Half of PAR would follow directly from the triangle used in part c).
I guess the model soln would do this as it's just one simple trig calculation
asin(2/3)
(edited 3 years ago)

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