A circle has center (1,3) and passes through (4,-1) How do you use the distance formula to find the length of the radius of the circle?

1 Answer
Apr 5, 2016

By definition the radius of a circle is the distance between the center and any point on the circumference of the circle.

Explanation:

If a circle has
#color(white)("XXX")#center at #(1,3)#
and
#color(white)("XXX")(4,1)# is a point on the circumference.

The radius of the circle is
#color(white)("XXxX")r=sqrt((1-4)^2+(3-1)^2)#

#color(white)("XXxX")=sqrt(3^2+2^2)#

#color(white)("XXxX")=sqrt(13)#