im stuck in getting the write answer for equation of circle with centre B for part (11) of the question.

I got (x-26)^2 + y^2 = 64 but the actual answer is

(x-24)^2 + y^2 = 64

what am i doing wrong!

help please!!

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# 2003 Paper 1 Question 11a) (1)

Started by tupacshakur, May 16 2005 01:05 PM

4 replies to this topic

### #1

Posted 16 May 2005 - 01:05 PM

WWE RAW IS WAR

### #2

Posted 16 May 2005 - 01:19 PM

dude! could u write down the question too.. cos i dont have the past papers and i could help if i knew the question

### #3

Posted 16 May 2005 - 01:19 PM

Got it, gimme a sec to draw it out and post it.

### #4

Posted 16 May 2005 - 01:31 PM

Right, basically the diagram should explain it all.

For the radius of circle B, just subtract the radius of circle A (sq.rt. 25 = 5) from the length of OA (which u calculate as 15), so you get the radius as 8.

For the centre, since the two circles are congruent and given that the broken line through A is the axis of symmetry, length of OA = OB, thus the centre of Circle B from Circle A will be equally distant to the centre of Circle O from Circle A, the latter of which (O to A) is 12 units, so the X coordinate of the centre of B is 24 (12 + 12). Hope that solves it. Cheers

For the radius of circle B, just subtract the radius of circle A (sq.rt. 25 = 5) from the length of OA (which u calculate as 15), so you get the radius as 8.

For the centre, since the two circles are congruent and given that the broken line through A is the axis of symmetry, length of OA = OB, thus the centre of Circle B from Circle A will be equally distant to the centre of Circle O from Circle A, the latter of which (O to A) is 12 units, so the X coordinate of the centre of B is 24 (12 + 12). Hope that solves it. Cheers

### #5

Posted 16 May 2005 - 02:05 PM

thanks!

WWE RAW IS WAR

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