trig question

[mustlearn]

I need to find the length across two canyons for a future bridge being built between them? I am 50 feet away from the future bridge and when I look at the opposite canyon from where I am standing its an 87 degree angle???

 

[mustlearn]

I believe the length of the bridge is the same as the length between the canyons. I also believe I'll need to deduct the 50 ft distance away I'm standing after finding my solution. Just not sure what formula to use sine, cosine, tangent?

 

[Dr.Peterson]

I need to find the length across two canyons for a future bridge being built between them? I am 50 feet away from the future bridge and when I look at the opposite canyon from where I am standing its an 87 degree angle???

I believe the length of the bridge is the same as the length between the canyons. I also believe I'll need to deduct the 50 ft distance away I'm standing after finding my solution. Just not sure what formula to use sine, cosine, tangent?

This makes no sense as written; I suspect you have incorrectly translated some words. Bridges don't go across two canyons (which are holes).

Perhaps the bridge is between two sides of one canyon, or between two cliffs. Possibly we can assume that you are 50 feet along one side, perpendicular to the direction of the bridge, and you are finding the angle (horizontally) from the near end to the far end; if so, then a tangent will be useful. But we need to be sure of these things.

Please quote exactly the problem as given to you (in the original language, if you translated it). And if you have a picture, or understand the problem well enough to make one, please attach that.