<PRE><B>Question 1114154</B>
105 and 84 have a common factor of 21
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the diagonal will cross 21 times as many tiles as the diagonal of a 105/21 = 5 by 84/21 = 4 tile rectangle.
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Since 5 and 4 have no common factor, the answer for the small 
rectangle is 5 + 4 - 1 = 8. 
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The final answer is 8*21 = 168
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Note For the 5 by 4 tile rectangle start at one corner with one tile. What happens every time the diagonal crosses either a horizontal or vertical line? Why do we need 5 and 4 to have no common factor?
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