The Tulip Tree 85 



Set a short pole in the earth near the tree. Measure 

 the height of the pole, the length of its shadow, and the 

 length of the shadow of the tree. The height of the 

 tree may then be computed as follows : Multiply the 

 length of the tree's shadow by the height of the pole, 

 and divide the product by the length of the pole's shadow. 

 The proportion may be expressed thus : The height of 

 the pole is to the length of its shadow as the height of 

 the tree is to the length of its shadow. 



the height of the pole : the length of its shadow : : the height of the tree 

 : the length of its shadow 



The pole might be 6 feet long, and its shadow 9 feet. 

 The shadow of the tree might be 60 feet. We should 

 then have this proportion : 6 : 9 : : x : 60, where x repre- 

 sents the height of the tree. Our answer to the question 

 then is : 6 X 60 = 9 X x, or x = 40, the height of the 

 tree. 



