trigonometry help

See the picture....Sean is at "A'  about 287 ft off the ground  ....LeAnn is at "B" ...her "horizontal" distance from Sean (CB) is about 410 ft.....the line of sight distance from Sean to LeAnn (AB) is 500 ft.

So..if you can imagine what we have...The line of sight distance is the hypoteneuse of a right triange. Sean's height off the ground is the adjacent side of an angle that measures (90 - 35) = 55 degrees. So we have

cos(55) = x / 500     where "x" is Sean's height off the ground

500cos(55) = x = about 287 ft.

I can provide a picture.....if you need it.....

I thought it would be tan?

No.... the tanget can't be used because we don't know the opposite side (the horizontal distance between Sean and LeAnn if Sean were standing on the ground) or the adjacent side (Sean's height off the ground)

so since i am looking for the adj side the hyp is 500 adj is x and 35 degrees is like him leaning to see her