SOLUTION: A tower is 18 feet above sea level, how far can a person see from the top if the radius (r) of earth is 3960 miles and 1 mile = 5280 feet? I started off by sketching a circle,

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Question 1066331: A tower is 18 feet above sea level, how far can a person see from the top if the radius (r) of earth is 3960 miles and 1 mile = 5280 feet?

I started off by sketching a circle, radius being 3960 but I don't know if this is geometry material as it is in an online mixed packet review. Going by drawing a line up then outward to make a tangent I got a right triangle, so I used Pythagorean Theorem = a^2+b^2=c^2 or 18^2+b^2=3960^2. I am sure I did it very wrong..

Found 2 solutions by Alan3354, stanbon:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
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Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A tower is 18 feet above sea level, how far can a person see from the top if the radius (r) of earth is 3960 miles and 1 mile = 5280 feet?
I started off by sketching a circle, radius being 3960 but I don't know if this is geometry material as it is in an online mixed packet review. Going by drawing a line up then outward to make a tangent I got a right triangle, so I used Pythagorean Theorem = a^2+b^2=c^2 or 18^2+b^2=3960^2.
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That looks good to me. You have a right angle at the tangent to the earth.
You have a right triangle with radius = 3960 mi
You have a line of sight from the top of the tower to the point of tangency
Let that distance be "x"
You have a 3rd side of the right triangle which 3960+18/5280 miles
So x^2 = (3960+18/5280)^2 - 3960^2 = 27
x = sqrt(27) = 3sqrt(3) miles
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Cheers,
Stan H.
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