
Thien D. answered 07/08/19
Duke MS Engineering Grad For Math Tutoring
Think of this problem as consisting of parts making up a whole. All the sides bust add up to the entire security fencing. We know three sides and the total length of all sides. We can subtract each of the three sides from the total length to get the last side!
To put this in terms of math:
476 1/24 = 102 2/3 + 125 3/4 + 120 5/8 + x,
where x is the fourth side.
Let's add the first two sides together first.
102 2/3 + 125 3/4 = 227 + 2/3 + 3/4
Using a least common denominator of 12:
227 + 8/12 + 9/12 = 227 + 17/12 = 227 + 1 + 5/12 = 228 5/12
Now lets add this sum to the third side.
228 5/12 + 120 5/8 = 348 + 5/12 + 5/8
Using a least common denominator of 24:
348 + 10/24 + 15/24 = 348 + 25/24 = 348 + 1 1/24 = 349 1/24
With this sum, we can simplify
476 1/24 = 102 2/3 + 125 3/4 + 120 5/8 + x
to
476 1/24 = 349 1/24 + x
Solving for x:
x = 476 1/24 - 349 1/24
= 127 ft.
Therefore, the length of the fourth side is 127 ft.