We are given an equation:

This is an equation of a circle. General form of a circle equation is:

Where:
a = x coordinate of a center
b = y coordinate of a center
r = radius of a circle
Motion detector can detect person anywhere within a boundary. The greatest distance at which detector can detect is at the edge of a circle. That distance, between detector and edge of circle, is equal to radius.
From the equation we have:

The greatest distance at which person can be detected is 4ft.
Answer:
s=461+123
Step-by-step explanation:
123 more is +125, and that's how many songs Joe, s, has.
V= pi x r^2 x h
V/(pi x h)=r^2
square root of [V/(pixh)]=r
Simply do 297500/350000 and you would get 85%