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help coordinate geometry q

hi i just cant work out how to do this question even tho its prob realy easy so if anyone can help it would be much appreciated

A and B are the points (-1, -6) and (5, -8) respectively. Which of the following points lie on the perpendicular bisector of AB? a). P(3,-4) b). Q(4, 0) c). R(5, 2) d). S(6,5)

thanx

Reply 1

CalculusMan

1) Find the gradient of AB
2) Find the midpoint of AB
3) Find the equation of the line perpendicular to AB through the mid point
4) Sub x and y into equation to see if they lie on it.

Reply 2

Chewwy

gradient of AB is? so perpendicular gradient is?

midpoint of AB is?

now you know a point on the line (the perpendicular bisector) and the gradient, so can find its formula. put in each of the x values of a), b), c) and d), and see which one produces the corresponding y value.