document.write( "Question 1057483: Z varies jointly as x^2 and y, and z = 20 when x = 2 and y = 3. Find z if x = 4 and y = 7/10 \n" ); document.write( "

Algebra.Com's Answer #672575 by Cromlix(4381) $\"\"$ $\"About$

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Hi there,
\n" ); document.write( "z varies jointly as x^2 and y
\n" ); document.write( "z = kx^2y
\n" ); document.write( "k is the constant of proportionality.
\n" ); document.write( "To find k use values, z = 20, x = 2 and y = 3
\n" ); document.write( "z = kx^2y
\n" ); document.write( "20 = k(2)^2 * 3 (* = times)
\n" ); document.write( "20 = k12
\n" ); document.write( "k = 20/12
\n" ); document.write( "k = 1.67 (2 decimal places)
\n" ); document.write( "Formula:
\n" ); document.write( "z = 1.67 * x^2 * y
\n" ); document.write( "Use formula:
\n" ); document.write( "z = 1.67x^2y
\n" ); document.write( "z = 1.67 * (4)^2 * 7/10
\n" ); document.write( "z = 18.70 (2 decimal places)
\n" ); document.write( "Hope this helps :-) \n" ); document.write( "

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