The diameter of a circle has endpoints A(9,-7) and B(-2,5). Find the length of the radius. Please I need some help and thanks.

Answer 1

use the distance formula √[(x2-x1)^2+(y2-y1)^2]

√([9-(-2)]^2+[-7-5]^2)

√[(11^2)+(-12)^2]

√(121+144)

√265

16.27882 is the length of the diameter

take half to get the radius

8.13941 is the radius

Answer 2

Hey there,

To find the midpoint (the center), you average the x and y coordinates of the diameter endpoints:

(((9-2)/2), (-7+5)/2) = (7/2, -1).

Next, use the distance formula to find the distance from one of the endpoints to the center of the circle to find the length of the radius:

d = sqrt((x1-x2)^2 + (y1-y2)^2) = sqrt( (7/2-9)^2 + (-1 + 7)^2) = sqrt(30.25 + 36) = sqrt(66.25) = 8.14