document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1097745>Question 1097745</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find a function p(x) for an arch that is 15 feet tall and 16 feet wide at the base  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #712184 by </B><A HREF=/tutors/aboutme.mpl?userid=htmentor><B>htmentor(1343)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=htmentor><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=htmentor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=712184\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The arch is in the shape of a parabola.  Let us choose the coordinates so that the vertex is at (0,15)<BR>\n" );
document.write( "Then the equation will take on the form p(x) = y = ax^2 + c<BR>\n" );
document.write( "Since the base is 16 feet wide, the parabola intersects the y-axis at the points (8,0) and (-8,0)<BR>\n" );
document.write( "When x = 0, the constant term c = 15<BR>\n" );
document.write( "Use one of the other points to find a:<BR>\n" );
document.write( "0 = a*8^2 + 15<BR>\n" );
document.write( "a = -15/64<BR>\n" );
document.write( "Thus one function which describes the arch is p(x) = (-15/64)x^2 + 15<BR>\n" );
document.write( "Note that the coefficient a is equal to -h/(b/2)^2, where h = the height and b = the base </SPAN>\n" );
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