Ah, yes. Perimeters. Perimeters are found by adding up the lengths of all the sides. But, as stated in the question description, there's one side missing. The way we find it is by subtracting the 6-foot side from the 16-foot side. The way this works is because 1) every corner is a right angle 2) and if that's so, the side with no number and the 6-foot side will add up to equal 16 feet, the same as the side opposite it.
If we subtract 6 from 16, we get 10. So, therefore, the missing side's length is 10 feet.
Now let's add all the sides together.
9 + 6 + 5 + 10 + 4 + 16 = 50
The perimeter of this shape is 50, if my geometry memory serves me correctly.
I hope this answers your question.
-Toremi
