Question

18. You are standing beside the Colorado River, 400 feet

from the base of Hoover Dam. Using an electronic distance
measuring device, you find the distance to the top of the dam
to be 965 feet. Use the diagram at the right to find the height
of the dam.
965ft
a.
561.6 ft
b. 781.6 ft
c. 566 ft
400 ft
166 ft

Answer 1

Answer: B. 781.6 feet approximately

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Work Shown:

The horizontal portion is 400+166 = 566 feet. Label this as 'a', so a = 566. The vertical side is unknown, so b = x. The hypotenuse is c = 965

Use the pythagorean theorem

a^2+b^2 = c^2

566^2+x^2 = 965^2

x^2 = 965^2 - 566^2

x = sqrt( 965^2 - 566^2 )

x = 781.58108984289 which is approximate

x = 781.6 feet when rounding to one decimal place