Hey, how do you know in a random question with 2 coordinates which is the x1 and y1 and which is the x2 and y2? I keep doing the x1/x2 and y1/y2 the wrong way round!
E.G. The line MN is the diameter of a circle, where M and N are (6,-4) and (0,-2) respectively. Find the radius of the circle
I know the forumla being the square root of (x2-x1)^2 + (y2-y1)^2...
But how on earth do you know from the question which is y2 and y1? I keep getting it wrong!
it really doesn't matter. just pick one point to be and the other to be . you'll get the same answer either way
Originally Posted by Danielisew
(you can try this, do it both ways and you will see. can you tell why this works out?)
Well I just tried it with the following:
I end up with the diameter being the square root of 40. Therefore, the radius is the square root of 20? It says the answer is the square root of 10! (Worried)
Thanks for your help, but I am still stuck..
Ok thanks very much..
Can you give me a quick lesson on that kinda thing where you cancel down surds? I can't do it and have no idea how square root of 40= 2 multiplied by square root 10..
It would be much appreciated!
Ok thanks a lot! I am sorted =)