Where the Sidewalk Ends

Today in the Afternoon classes we went outside and measured the sidewalk from one green x to the next.  You were asked to find a measurement for this distance.

What was the distance between the two x's?
What method did you use to measure the distance?
What did you use to calculate your answer (tools used)?

Leave a comment behind with your answer.  Please ensure that your room number is there too.  (i.e. Carlo 816)