document.write( "Question 1171136: The cable of a suspension bridge hangs in a shape of a parabola. The towers supporting the cable are 400 feet apart and 150 feet in height. If the cable, at its lowest, is 30 feet above the bridge at its midpoint how high is the cable 50 feet away(horizontally) from either tower? \n" ); document.write( "
Algebra.Com's Answer #796035 by ankor@dixie-net.com(22740)\"\" \"About 
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A big mistake here, I assumed the towers were 400 ft from the midpoint, not so
\n" ); document.write( "they are 200 ft from the center
\n" ); document.write( "here is is again
\n" ); document.write( "let the midpoint be 0, 30 on a graph, then find the equation for 200, 150
\n" ); document.write( "x=200, y=150
\n" ); document.write( "200^2a + 30 = 150
\n" ); document.write( "40000a = 150-30
\n" ); document.write( "a = 120/40000
\n" ); document.write( "a = .003
\n" ); document.write( "The equation
\n" ); document.write( "y = .003x^2 + 30
\n" ); document.write( "graphically
\n" ); document.write( "\"+graph%28+300%2C+200%2C+-250%2C+250%2C+-20%2C+200%2C+.003x%5E2%2B30%2C+98%29+\"
\n" ); document.write( ":
\n" ); document.write( "\"how high is the cable 50 feet away(horizontally) from either tower?\"
\n" ); document.write( "200-50 = 150, find y when x = 150
\n" ); document.write( "y = .003(150^2) + 30
\n" ); document.write( "7 = 67.5 + 30
\n" ); document.write( "y = 97.5 is the height of the cable at this point (Green line)
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