document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1207680>Question 1207680</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The numbers $24^2 = 576$ and $56^2 = 3136$ are examples of perfect squares that have a units digits of $6.$\r<BR>\n" );
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document.write( "If the units digit of a perfect square is $5,$ then what are the possible values of the tens digit? </SPAN>\n" );
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document.write( "ANSWER: 2 only<br><BR>\n" );
document.write( "If the perfect square n^2 has units digit 5, then n itself has units digit 5, so it is of the form 10m+5, where m is an integer.  Then<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%5E2=%2810m%2B5%29%5E2=100m%5E2%2B100m%2B25=100%28m%5E2%2Bm%29%2B25 ALIGN=MIDDLE  ALT=\"n%5E2=%2810m%2B5%29%5E2=100m%5E2%2B100m%2B25=100%28m%5E2%2Bm%29%2B25\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "So n^2 is equal to 100 times some integer, plus 25; that means the last two digits are always 25.<br><BR>\n" );
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