Question 375596
Hat size 6 7/8 
head circumference 21 3/5 
head circumference 55.
hat size = x
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6 7/8 = 55/8
21  3/5 = 108/5
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{{{(55/8)/((108)/5)= x/55}}}
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{{{(55/8)*(5/108)=x/55}}}
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multiply by 55
{{{55*(55/8)*(5/108)=x*(cross(55))/(cross(55))}}}
{{{(55*55*5)/(8*108)=x}}}
x=17 1/2
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m.ananth@hotmail.ca