trigonometry

[ruby shore]

how does this work??

[dry copper]

Let's denote some variables like on the picture.
Then we have:
cot(α) = y/h
cot(β) = z/h
So:
y = h cot(α)
z = h cot(β)
Then we notice that x = y + z. So:
x = h(cot(α) + cot(β))