Sine, cosine law
posted by Nada on .
The Pont du Gard near Nimes, France is a roman aqueduct. An observer in a hot air balloon some distance away from the aqueduct determines that the angle of depression to each end is 54 degrees and 71 degrees respectively the horizontal distance between the balloon and aqueduct is 270.0 m. Calculate the length of the aqueduct to the nearest thenth of a metre.

I noticed you posted the same question before.
I cannot reconcile your data with a diagram I am attempting.
Your call of angles of depression suggests the balloon is above the aquaduct, but then you give the horizontal distance between the balloon and the aquaduct.
Is the balloon in a plane parallel to the plane of the bridge and the distance between those planes is 270 ?
Are we working in 3 separate planes in 3D ? 
I'm not sure if it is parllel, it dosent have a diagram so it got me confused! But I know it is not in 3D, the answer in the txtbook is 299.7m, I just need the method to get it