One of the best approaches to address similar triangle problems is to illustrate the problem. Below is an image of how a person is standing from the tree with ΔABC ~ ΔDEC, CE ~ BC, and DE ~ AB.
Mathematically, we have
[tex] \frac{CE}{BC} = \frac{DE}{AB}[/tex]
and working on the equation,
[tex] \frac{1.8}{(7 + 1.8)} = \frac{1.3}{AB} [/tex]
[tex] \frac{1.8}{8.8} = \frac{1.3}{AB} [/tex]
[tex] AB = \frac{(1.3)(8.8)}{1.8} [/tex]
[tex] AB = 6.36 [/tex]
Thus, the height of the tree is 6.36m.
Answer: 6.36 m
