document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1173968>Question 1173968</A>: <I><SPAN STYLE=\"word-break: break-all;\"> the intensity I of illumination from a light source is inversely proportional to the square of the distance d from the source. Suppose the intensity is  320 candela at a distance of 10 feet from a light source.\r<BR>\n" );
document.write( "\n" );
document.write( "a. What is the intensity at 2 feet from the​ source?<BR>\n" );
document.write( "b. How far away from the source will the intensity be 400 ​candela?\r<BR>\n" );
document.write( "\n" );
document.write( "a. the intensity of illumination is ____  at a distance of 2 feet from the source. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #799329 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=799329\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the intensity I of illumination from a light source is inversely proportional to the square of the distance d from the source.<BR>\n" );
document.write( "make an equation from this information given<BR>\n" );
document.write( "I = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=k%2Fd%5E2 ALIGN=MIDDLE  ALT=\"k%2Fd%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > where <BR>\n" );
document.write( " I=illumination in candelas;<BR>\n" );
document.write( " d=distance from light source, <BR>\n" );
document.write( " k=constant<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Suppose the intensity is 320 candela at a distance of 10 feet from a light source.<BR>\n" );
document.write( "Find k with these values<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=k%2F10%5E2 ALIGN=MIDDLE  ALT=\"k%2F10%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 320<BR>\n" );
document.write( "k = 320 * 100<BR>\n" );
document.write( "k = 32000<BR>\n" );
document.write( ":<BR>\n" );
document.write( "a. What is the intensity at 2 feet from the​ source?<BR>\n" );
document.write( "I = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=32000%2F2%5E2 ALIGN=MIDDLE  ALT=\"32000%2F2%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "I = 8000 candelas<BR>\n" );
document.write( ":<BR>\n" );
document.write( "b. How far away from the source will the intensity be 400 ​candela?<BR>\n" );
document.write( "400 = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=32000%2Fd%5E2 ALIGN=MIDDLE  ALT=\"32000%2Fd%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "400d^2 = 32000<BR>\n" );
document.write( "d^2 = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=32000%2F400 ALIGN=MIDDLE  ALT=\"32000%2F400\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "d^2 = 80<BR>\n" );
document.write( "d = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sqrt%2880%29 ALIGN=MIDDLE  ALT=\"sqrt%2880%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "d = 8.9 ft<BR>\n" );
document.write( ":<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );