



 
Hi Joyce, You need to assume that the surface of the barge is on the surface of the water so that you are 100 feet above the barge. In the sketch above B is the bridge surface and C is the front end of the barge. The angle of depression is 29.04 degrees and hence
Solve for AB In a similar fashion you can find the horizontal distance to the rear of the barge and hence determine the length of the barge. Harley  


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