Short Answer: AB
Argument
Take F to be the center. The line segment that IS a diameter or radius must either go through F (that would make the line a diameter) or to be a radius the segment mus end in F and touch the circumference once. See below.
The diameter must not only go through F, it must touch the circumference in two places. EFB is a diameter. So is AFC
The radius must have 1 endpoint at the center and one endpoint on the circumference. DF is a radius.
So what isn't? Answer: AB isn't. It neither goes through F nor is F one of the end points.
Answer: AB
= (2*10) + (-3*-4) + 5 (* means multiply)
= 20 + 12 + 5
= 37
Part A:
Total boards = 3 sections of 4 boards = 12 boards
Alex paints: 1/6 of 12 boards = 2 boards
Bobby paints: 2 x Alex = 1/3 of 12 boards = 4 boards
Charles paints: 1 board
David paints: 12 - (Alex + Bobby + Charles) = 12 - 7 = 5 boards
-This means that David painted the largest part of the fence
Part B:
The fraction of the fence that David painted = 5 boards /12 total boards = 5/12
Simplified would be: 3s + 2