1. find slope for the line AB, say m1

2. the slope of the line perpendicular to AB is

m2 = – 1/(m1)

tip: to find slope of line passing A(4,19) and B(-3,5)

slope m1= (yB -yA) / (xA – xB)

where

A(xA, yA) = A(4,19)

B(xB, yB) = B(-3,5)

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circle centered at the origin runs through the point (9, 12). What is the radius of the circle?

tip: radius of the circle at origin running through the point(x,y)

radius = sqrt(x^2, y^2)

radius = sqrt (9^2 + 12^2) = sqrt(81 + 144)

radius = sqrt(225) = 15

find the slope of line AB, then find the number that when the nunbers are multiplied, they equal -1.

2. 15

use the distance formula to find distance between center & origin .