On Slope

1. Case I: Observer at the middle of the tree

AB = DO (Tan u + Tan d)

2. Case II: Observer below the bottom of the tree,

BD = AB-AD= AO (Tan u –Tan d)

3. Case III: Observer is above the base and top of the tree

Height of the tree, AB= ED. (Tan β-Tan α) = EB. Cosβ. (Tan β-Tan α)