Thread: cartesian plane

find the radius of a circle with center at (-2, 1), if a chord length of 10 is bisected at (-3, 0).

can you help me with this one? i think ill know how to solve it if i know the drawing.

by the way, answer is 3┌3 or 5.196 according to our prof.

Originally Posted by proview

find the radius of a circle with center at (-2, 1), if a chord length of 10 is bisected at (-3, 0).

can you help me with this one? i think ill know how to solve it if i know the drawing.

by the way, answer is 3┌3 or 5.196 according to our prof.

yes, that's the answer. i wish i had my graphing software and stuff on this PC so that i could show you the diagram.

anyway, plot the center, and draw a line connecting it to (-3,0). the chord is perpendicular to this line. so draw that (the line you drew first is the perpendicular bisector of the chord). then use the formula , with and as shown here. you can figure out the value of d using Pythagoras' theorem, and then just solve the equation for r

thanks for help. i got the drawing and realized that you can use Pythagorean theorem to solve it all the way.