Answer: 11
The perimeter as a mixed number is P = 11 & 4/5, but it seems like your teacher only wants the whole part of the answer. So you'll just type 11.
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Work Shown:
1/2 = 0.5
2 & 1/2 = 2 + 1/2 = 2 + 0.5 = 2.5
This shows that L = 2.5 ft
Similarly, W = 3.4 ft because 3+2/5 = 3+0.4 = 3.4
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Plug those L and W values into the perimeter formula
P = 2L + 2W
P = 2*2.5 + 2*3.4
P = 5 + 6.8
P = 11.8
now convert back to a mixed number
11.8 = 11 + 0.8
11.8 = 11 + 8/10
11.8 = 11 + 4/5
11.8 = 11 & 4/5
The perimeter is 11 & 4/5 ft. In other words, the perimeter is 11 whole feet plus an additional 4/5 of a foot.
Your teacher seems to only want the whole part of the answer, assuming they only want the stuff in the box indicated with a question mark. If that's the case, then you'll type 11 into the box to write the final answer.