We can first use this..... [ We're using 13.413 mi......??? ]
tan (6.1) = h/x → h = x*tan(6.1)
And then we have
tan (8.1) = h/ [13.413 - x] = [ x*tan(6.1)] / [13.413 - x] ....so we have
tan (8.1) = [ x*tan(6.1)] / [13.413 - x]
[13.413 - x] tan (8.1) = x*tan(6.1)
13.413 tan (8.1) - x* tan (8.1) = x* tan (6.1)
13.413 tan (8.1) = x* tan (8.1) + x* tan (6.1)
13.413 tan (8.1) = x * [ tan (8.1) + tan (6.1)]
x = 13.413 tan (8.1) / [ tan (8.1) + tan (6.1)] ≈ 7.66 mi
And the height is x*tan(6.1) = 7.66 * tan(6.1) ≈ .8187 mi
Here's a pic :

