Well let's see.
If the figure is split up into 10 pieces, then
each piece is 1/10 of the whole figure.
If 2 of the pieces are shaded, then
2/10 of the whole figure is shaded.
How many pieces are left ?
There were 10 pieces all together, and
2 of them are shaded. Hmmm. I think
there are probably (10 - 2) = 8 of them left
that are not shaded.
8 pieces makes 8/10 of the whole figure.
First turn 1/2 to 2/4 so you have a common denominator.
Next turn the mixed numbers into improper fractions:
11 3/4 --> 47/4 and 8 2/4 --> 34/4
Subtract:
47/4 - 34/4 = 13/4
Divide:
13/4 = 3.25
3.25/2 --> 1.625 or 1 5/8
Therefore, he will have to place it 1 5/8 feet from each side
Hope this helps!
2:5
4:10
8:20
16:40
Hope that helps:)