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# P3 simple circle q. watch

1. (x-12)^2 + (y-5)^2 = 25
find the greatest and the least distance between circumference and origin

ans: 8,18

I dunno how to do it tho
2. (Original post by etomac)
(x-12)^2 + (y-5)^2 = 25
find the greatest and the least distance between circumference and origin
ans: 8,18
I dunno how to do it tho
A quick sketch will help you to realise that the least distance is the distance from the origin to the centre minus the radius while the greatest distance is the distance to the origin plus the radius.

Looking at the circle equation will show you that the circle has centre (12, 5) and radius 5.

Using pythagoras, the distance to the centre of the circle from the origin is rt [ 12 ^2 + 5^2 = 13

Hence the least distance is 13-5=8
The greatest distance is 13+5=18.

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Updated: December 20, 2004
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