document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=511668>Question 511668</A>: <I><SPAN STYLE=\"word-break: break-all;\"> please help me.......<BR>\n" );
document.write( "two school buildings are 7 inches apart on a city map. if the map scale is 4 inches to 3 miles, find the actual distance between the buildings. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #342359 by </B><A HREF=/tutors/aboutme.mpl?userid=bucky><B>bucky(2189)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=bucky><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=342359\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This problem can be done using a proportion. A proportion is an equality between two ratios.<BR>\n" );
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document.write( "It might help you to read this problem as \"4 inches is to 3 miles as 7 inches is to X miles.\" <BR>\n" );
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document.write( "Then you can set up two ratios. The first ratio is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4+in%2F3+mi ALIGN=MIDDLE  ALT=\"4+in%2F3+mi\"   DISABLED_style= \"max-width:90%; height:auto;\" >. Note that the inches are in the numerator and the miles are in the denominator. For the second ratio you need to arrange it so the numerator also has the same units as the numerator of the first ratio. Also the denominator has to have the same units as the denominator of the first ratio. Therefore, this second ratio has to have the inches in the numerator and the miles in the denominator. This second ratio is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7+in%2FX+mi ALIGN=MIDDLE  ALT=\"7+in%2FX+mi\"   DISABLED_style= \"max-width:90%; height:auto;\" >. The X in the denominator represents the unknown miles you have been asked to find.<BR>\n" );
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document.write( "Next you form the proportion by setting these two ratios equal as follows. (I left the dimensions out of the equation to reduce the notation.)<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4%2F3+=+7%2FX ALIGN=MIDDLE  ALT=\"4%2F3+=+7%2FX\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "A simple way to solve proportions involves cross-multiplying. Multiply the each of the numerators by the denominator from the other side of the equation. For this problem multiply the numerator 4 by the denominator X. The result is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4X ALIGN=MIDDLE  ALT=\"4X\"   DISABLED_style= \"max-width:90%; height:auto;\" >. Then multiply the numerator 7 times the denominator 3. This result is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=21 ALIGN=MIDDLE  ALT=\"21\"   DISABLED_style= \"max-width:90%; height:auto;\" >. (Note that if you draw a line connecting the 4 and the X and another line connection the 7 and the 3, the two lines cross through the equal sign of the proportion. This is why they are called cross-products and the process is called cross-multiplying.)<BR>\n" );
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document.write( "Next, set the two cross-products equal as follows:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4X+=+21 ALIGN=MIDDLE  ALT=\"4X+=+21\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Solve for the unknown miles (X) by dividing both sides of this equation by 4 to get:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=X+=+21%2F4 ALIGN=MIDDLE  ALT=\"X+=+21%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "When you do the division of the right side you get the answer:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=X+=+5%261%2F4 ALIGN=MIDDLE  ALT=\"X+=+5%261%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "So the answer you are looking for is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5%261%2F4 ALIGN=MIDDLE  ALT=\"5%261%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" > miles.<BR>\n" );
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document.write( "This means that on a map that is scaled 4 inches to 3 miles, a map measurement of 7 inches represents <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+5%261%2F4 ALIGN=MIDDLE  ALT=\"+5%261%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" > miles.<BR>\n" );
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document.write( "Hope this helps you to understand how proportions can be used to solve problems such as this one.<BR>\n" );
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