Estimate the height of the goal post. Draw a diagram and list all of the supportive assumptions and calculations.
Time of day 1:38 on 1/11/2009
(a) length of stride: 2.08ft
(b) Total outside shadow strides: 36
BIG SHADOW LENGTH (a) times (b)
(c) SHOE SIZE: 11/12(d) Your shadow in baby steps: 12
SMALL SHADOW LENGTH: (C) times (d)
Your Height: (in feet): 5.58

The ratio of the length of your own shadow to your height is the same as the ratio of the length of the goal post shadow to its height, Looks like you have all the data you need to determine the height of the goal posts. Let us know what you come up with, and we'll be glad to check it.