document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=238005>Question 238005</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 4. ABCD is a rectangle. Find mB. <BR>\n" );
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document.write( "A.   45° <BR>\n" );
document.write( "B.   90° <BR>\n" );
document.write( "C.   100° <BR>\n" );
document.write( "D.   180° \r<BR>\n" );
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document.write( "5. ABCD is a rectangle. AD = 3 and AB = 10. Find CD. <BR>\n" );
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document.write( "A.   3 <BR>\n" );
document.write( "B.   6 <BR>\n" );
document.write( "C.   10 <BR>\n" );
document.write( "D.   20 \r<BR>\n" );
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document.write( "6. ABCD is a rectangle. AC = 12. Find BE. <BR>\n" );
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document.write( "A.   6 <BR>\n" );
document.write( "B.   8 <BR>\n" );
document.write( "C.   10 <BR>\n" );
document.write( "D.   12 \r<BR>\n" );
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document.write( "7. Find the value of x so that ABCD is a rectangle, if AD = 5x &#150; 6 and BC = 3x + 4. <BR>\n" );
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document.write( "A.   3 <BR>\n" );
document.write( "B.   4 <BR>\n" );
document.write( "C.   5 <BR>\n" );
document.write( "D.   6 <BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #174934 by </B><A HREF=/tutors/aboutme.mpl?userid=jsmallt9><B>jsmallt9(3758)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jsmallt9><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=174934\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 4. ABCD is a rectangle. Find mB. <BR>\n" );
document.write( "All the angles of every rectangle are 90 degrees.<br> <BR>\n" );
document.write( "5. ABCD is a rectangle. AD = 3 and AB = 10. Find CD. <BR>\n" );
document.write( "AD and AB are the length and width of the rectangle. CD is the side opposite to    AB. Opposite sides of all rectangles are congruent so AB = CD = 10.<br><BR>\n" );
document.write( "6. ABCD is a rectangle. AC = 12. Find BE. <BR>\n" );
document.write( "BE? I think this is BD. If so, AC and BD are diagonals of the rectangle. Since the two diagonals of every rectangle are congruent, AC = BD = 12<br><BR>\n" );
document.write( "7. Find the value of x so that ABCD is a rectangle, if AD = 5x - 6 and BC = 3x + 4. <BR>\n" );
document.write( "This problem is incomplete. There is no way to solve it with the given information. Either you have left something out or the problem is invalid.<br><BR>\n" );
document.write( "However, we can find the value of x that makes AD = BC. This would make opposite sides equal which must be true if ABCD is a rectangle.<br><BR>\n" );
document.write( "To find an x that makes the opposite sides equal:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5x-6+=+3x%2B4 ALIGN=MIDDLE  ALT=\"5x-6+=+3x%2B4\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Now we solve this. Subtract 3x from each side:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2x+-+6+=+4 ALIGN=MIDDLE  ALT=\"2x+-+6+=+4\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Add 6 to each side:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2x+=+10 ALIGN=MIDDLE  ALT=\"2x+=+10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Divide both sides by 2:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+5 ALIGN=MIDDLE  ALT=\"x+=+5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "So the only value for x that makes the opposite sides AD and BC equal is 5. If x is any other number ABCD cannot be a rectangle. But if x is 5, then ABCD could be but does not have to be a rectangle. (ABCD could also be a parallelogram or an isosceles trapezoid if x = 5.)<br><BR>\n" );
document.write( "In order to show that a quadrilateral is a rectangle we must show, directly or indirectly, that it is a parallelogram with 4 right angles. This cannot be done with the information you provided, regardless of the value(s) of x. </SPAN>\n" );
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