document.write( "Question 122377: what does a close circle and an open circle mean on a number line? \n" ); document.write( "

Algebra.Com's Answer #89855 by solver91311(24713) $\"\"$ $\"About$

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document.write( "Open and closed circles are used to mark the end points of intervals.\r\n" );
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document.write( "If the circle is open, it means the end point is NOT included in the interval,\r\n" );
document.write( "but if the circle is closed, it means the end point is included.\r\n" );
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document.write( "Consider the interval .  In this interval, the low endpoint, the 3,\r\n" );
document.write( "is not included because you have a 'less than' sign.  The high endpoint, the 6,\r\n" );
document.write( "is included because you have a 'less than or equal' sign.  It is the presence\r\n" );
document.write( "or absence of the 'or equal' part that determines whether the circle is closed\r\n" );
document.write( "or open.\r\n" );
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document.write( "The interval  would be marked on the number line with an open\r\n" );
document.write( "circle at 3, a closed circle at 6, and a heavy line connecting the two.\r\n" );
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