document.write( "Question 596198: A laboratory designed a radio telescope with a diameter of 280 feet and a maximum depth of 50 feet. the graph depicts a cross section of this telescope. find the equation of the parabola. \n" ); document.write( "
Algebra.Com's Answer #377589 by stanbon(75887)\"\" \"About 
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A laboratory designed a radio telescope with a diameter of 280 feet and a maximum depth of 50 feet. the graph depicts a cross section of this telescope. find the equation of the parabola.
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\n" ); document.write( "You could have a parabola passing through (-140,0),(0,280),(140,0)
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\n" ); document.write( "Form ax^2 + bx + c = y
\n" ); document.write( "Substitute each of the point values pairs to get 3 equations.
\n" ); document.write( "140^2a -140b + c = 0
\n" ); document.write( "0a + 0b + c = 280
\n" ); document.write( "140^2a + 140b + c = 0
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\n" ); document.write( "Solve the system to get:
\n" ); document.write( "a = -1/170
\n" ); document.write( "b = 0
\n" ); document.write( "c = 200
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\n" ); document.write( "y = (-1/170)x^2+280
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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