SOLUTION: A cirlce has a centre (4,-5), if a diameter is PR and P=(8,1) calculate the coordinates of R.

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Question 836276: A cirlce has a centre (4,-5), if a diameter is PR and P=(8,1) calculate the coordinates of R.
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
We use the midpoint formula, but in reverse to get the following

(x+8)/2 = 4

x+8 = 2*4

x+8 = 8

x = 8-8

x = 0

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(y+1)/2 = -5

y+1 = 2*(-5)

y+1 = -10

y = -10-1

y = -11

So the point R is (0,-11)