Answer:
(a)The missing measurements are 9 feet and
.
(b)Therefore, the length of the fence is 
Step-by-step explanation:
The diagram of the yard is attached below.
(a)I have labeled the missing dimensions of the yard as x and y.
Therefore:

Similarly:

The missing measurements are 9 feet and
.
(b)Length of the Fence
The fence is rectangular shaped with:
Length = 
Width = 
Perimeter of a Rectangle = 2(L+W)
Therefore, the length of the fence

The best measure of center tendency for this set of data would be the median. It is the best measurement because the data set has an outlier. The outlier is the 30. So to find the median we first order the data set and then find out if the set is an even or odd set. This set is even so we just chose the middle number. If the set was even, we would add the two center number and divide them by 2.
3, 3, 4, 4, 4, 5, 5, 5, 30
The center tendency = 4
The first one
2,6,8,3,7,9,4,9,8,7,3,2,8,11,3