EUCALYPTUS. 



tree from which the measure was made. Then at about a 

 quarter of the distance between the stake and the tree a 

 pole must be raised until its top comes into the line be- 

 tween the stake and the top of the tree. This can be 

 seen, of course, by the observer looking over the top of 

 the stake. 



The accompanying diagram explains the rest. 



r 



To calculate the height of a tree, AB:BF = AD:DE. 

 Suppose A B = 10 feet, B F = 8 feet and A D = 100 feet, 



then 10 : 8 = 100 = D E. 

 Hence D E = 80 feet and the height of the tree = 80 D C 



the height of the man from the ground. 



