A 4-ft vertical post casts a 12-in shadow at the same time a nearby cell phone tower casts a 118-ft shadow. How tall is the cell phone tower?

height of vertical post = 6ft

its shadow = 20 in

For all shadows cast at the same time, the ratio of the height of a shadow-casting structure to the length of its shadow is the same. (Assuming, of course, that it's the sun casting the shadows.)

So the ratio is  

4 feet / 12 inches = 4 feet / 1 foot = 4/1 = 4,

and if h is the height of the cell tower,

h/122 feet = 4

h = 4 x 122 feet = 488 feet. < Final answer

Hope I helped,

-Adrian Velez

Step-by-step explanation:

b. astronomers