document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1021014>Question 1021014</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The intensity I of light from a light bulb varies inversely as the square of the distance d from the light bulb. Suppose I is 810 w/m^2 when the distance is 3 m.  How much farther would it be to a point where the intensity is 160 w/m^2. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #636925 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=636925\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The intensity I of light from a light bulb varies inversely as the square of the distance d from the light bulb. Suppose I is 810 w/m^2 when the distance is 3 m.  How much farther would it be to a point where the intensity is 160 w/m^2.\r<BR>\n" );
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document.write( "the formula is i = k / d^2\r<BR>\n" );
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document.write( "i equals the intensity of the light in watts per square meter.<BR>\n" );
document.write( "d equals the distances from the light bulb in meters.<BR>\n" );
document.write( "k is the constant of variation.\r<BR>\n" );
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document.write( "i is 810 watts per square meter when d is 3 meters.\r<BR>\n" );
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document.write( "the formula if i = k / d^2 becomes 810 = k / 3^2.\r<BR>\n" );
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document.write( "this becomes 810 = k / 9.\r<BR>\n" );
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document.write( "solve for k to get k = 810 * 9 = 7290.\r<BR>\n" );
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document.write( "you are asked to determine how much farther away from the light bulb would a point be if the intensity of the light was 160 watts per square meter.\r<BR>\n" );
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document.write( "k is the constant of variation, so it stays the same.\r<BR>\n" );
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document.write( "the formula of i = k / d^2 becomes i = 7290 / d^2.\r<BR>\n" );
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document.write( "when i = 160, the formula becomes 160 = 7290 / d^2.\r<BR>\n" );
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document.write( "solve for d^2 to get d^2 = 7290 / 160 = 45.5625.\r<BR>\n" );
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document.write( "solve for d to get d = sqrt(45.5625) = 6.75 meters.\r<BR>\n" );
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document.write( "the intensity of light would be 160 watts per square meter when the distance from the light bulb is 6.75 meters.\r<BR>\n" );
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document.write( "that would be 6.75 - 3 = 3.75 meters further away.\r<BR>\n" );
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document.write( "that's your solution.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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