Question

p(3,5) and q(7,-1) are the end points of a diameter of a circle. what is the length of a radius of the circle

Answer 1

$d= \sqrt{(7-3)^2+(-1-5)^2} = \sqrt{16+36} = \sqrt{52} =2 \sqrt{13} \\ \\ r= \frac{d}{2}= \frac{2 \sqrt{13} }{2} = \sqrt{13}$

the length of a radius of the circle is √13