Answer:
21
Step-by-step explanation:
50 - 23.75 = 26.25
26.25 ÷ 1.25 = 21
I genuinely don't know what the point is of the table, where do you use it for?
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.
1) 4 divided by 7 = 0.57
2) 4 times 5 = 20 and 4 times 8 = 32
3) 20 plus 32 = 52
4) 0.57 times 52 = 29.64
5) answer : 29.64
i hope this is correct. i tried to break it down.