Question 363000
A 28 ft. ladder is leaning halfway up a 40 foot building. How far from the building should ladder be placed? (Round answer to the nearest foot) 
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halfway up the building would be 20 ft.
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apply pythagorean theorem
let x = distance from building
then

x^2 + 20^2 = 28^2

x^2 = 28^2 - 20^2

x^2 = 784 - 400

x^2 = 384

x = 19.5959

x = 20 feet (rounded)