document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1112773>Question 1112773</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Pete Zarilla sells 10-inch pizzas for $4.30, 12 inch pizzas for 5.88, and 14 inch pizzas for 7.78. Assume that the price is a quadratic function of the diameter.\r<BR>\n" );
document.write( "\n" );
document.write( "a) Write the particular equation expressing price in terms of diameter.<BR>\n" );
document.write( "b)predict the price of a 5 inch pizza.<BR>\n" );
document.write( "c) If a pizza sells for $20, what would you expect the diameter to be?<BR>\n" );
document.write( "d) what is the significance of the fact that the price- intercept is greater than zero? Suggest what it might represent.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #727803 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=727803\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 4.30=ax^2+bx+c<BR>\n" );
document.write( "x=5<BR>\n" );
document.write( "4.30=25a+5b+c<BR>\n" );
document.write( "5.88=36a+6b+c<BR>\n" );
document.write( "7.78=49a+7b+c\r<BR>\n" );
document.write( "\n" );
document.write( "1.58=11a+b<BR>\n" );
document.write( "1.90=13a+b<BR>\n" );
document.write( "0.32=2a<BR>\n" );
document.write( "a=0.16<BR>\n" );
document.write( "b=-0.18<BR>\n" );
document.write( "c=1.2\r<BR>\n" );
document.write( "\n" );
document.write( "C=0.16x^2-0.18x+1.2, in dollars, with x= radius.<BR>\n" );
document.write( "when diameter is 5, x=2.5<BR>\n" );
document.write( "C=1-0.45+1.20=$1.75<BR>\n" );
document.write( "---<BR>\n" );
document.write( "20=0.16x^2-0.18x+1.2<BR>\n" );
document.write( "0=0.16x^2-0.18x-18.8<BR>\n" );
document.write( "x=(1/0.32)(0.18+/- sqrt(0.0324+12.032); sqrt term=3.47<BR>\n" );
document.write( "x=3.125*3.65, only positive root<BR>\n" );
document.write( "=11.41<BR>\n" );
document.write( "diameter is 22.82 inches.<BR>\n" );
document.write( "Can do a rough check by using C=Kx^2, and K is about 0.15 for simple cost is a function of radius squared function (a little larger for smaller).  That would be $19.52, which is a reasonable check.  \r<BR>\n" );
document.write( "\n" );
document.write( "The price intercept >0 could be considered the contribution of the overhead for making a pizza, having the ingredients there, the building, etc.\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );