Answer:
12.1 in
Explanation:
what is your problem with that ? you don't understand what "perimeter" means ?
it means the whole way around the figure 1 time. it is the sum of all sides.
so, when we have the sum but miss one element of the dimensions numbers ?
what do you think we do ?
we calculate the difference between the sum of the elements we have, and the total sum.
this difference must be the missing side length.
so, the total is 136.8 in.
what we have is
44.4+10+10+12.7+22.2+12.7+12.7 =
= 44.4 + 20 + 3×12.7 + 22.2 = 124.7 in
the difference is
136.8 - 124.7 = 12.1 in
that is our missing side length.
you see, the picture tries to convince us that all the angles are right angles (90°). in that case the missing side length would be simply
44.4 - 12.7 - 22 2 = 9.5 in.
but no, it is good that we did not simply fall for an optical illusion. the absolute numbers tell us that some of the angles must be slightly different from 90°.
in case of doubt always rely on the absolute numbers.