



 
Hi Kenneth, Look at the fractions first and put each of them in lowest terms. \[\frac{18}{27} = \frac{9 \times 2}{9 \times 3} = \frac23\] and \[\frac{26}{39} = \frac{2 \times 13}{3 \times 13} = \frac23 .\] Thus the first pair of fractions are equal. Try the second pair. Since $\large \frac{18}{27} = \frac{26}{39}$ we know that 18:27 as 26:39. What about 18:26 and 27:39? This makes you wonder, if a:b as c:d then is a:c as b:d? Can you prove or disprove this? Penny  


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