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Question 1120520:  A street in manila composing of two lanes each 14ft wide runs through a semi circular tunnel with a radius of 16ft. What is the height of the tunnel at the edge of each lane? 
 Answer by rothauserc(4718)      (Show Source): 
You can  put this solution on YOUR website! for a circle, we know x^2 +y^2 = r^2, where r is the radius of the circle 
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therefore, for the semicircle we have y = square root(r^2 -x^2), where the square root is positive for the semi circular tunnel 
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let the center for the semicircle tunnel be (0,0), then 
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the outside edges of the two lanes are -14 and 14 
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Note that y is the height of the tunnel  
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y = square root(256-x^2) 
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y = square root(256-196) = 7.746 
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the tunnel is 7.746 feet high at each edge 
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