anonymous one year ago A circle has its center at the origin, and (5, -12) is a point on the circle. How long is the radius of the circle? 5 12 13

1. zzr0ck3r

You want the distance from that point to the origin. Do you know how to find the distance between two points?

2. anonymous

|dw:1433281453913:dw| Simply use the triangle formula for perpendicular triangles, which says: $c^2 = a^2 + b^2$ Where c is hyphotenus, a and b are sides. In here $r^2 = 12^2 + 5^2 = 169$ $r = \sqrt{169} = 13$

3. campbell_st

well a simple method is to know the standard form of the equation of the circle $(x - h)^2 + (y - k)^2 = r^2$ (h, k) is the centre... so substitute the given values then substitute the point this will allow you to calculate r^2 and then r... the radius... hope it helps

4. anonymous

thank you:)

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