What is the median of the height of buidings in feet:

8 , 12 , 6 , 8, 12 , 18 , 11, 20 , 8

The median is the middle value when a set of numbers is arranged in order from least to greatest.

Arranging the heights from least to greatest:

6, 8, 8, 8, 11, 12, 12, 18, 20

There are nine heights, so the middle value is the fifth one:

6, 8, 8, 8, [11], 12, 12, 18, 20

Therefore, the median height is 11 feet.

To find the median of a set of numbers, we need to arrange the numbers in ascending order first:

6, 8, 8, 8, 11, 12, 12, 18, 20

Next, we determine the middle value. Since there are 9 numbers in the set, the middle value is the 5th number, which is 11.

Therefore, the median of the height of the buildings is 11 feet.