Monthly Archives: August 2012

Nine Dates

You are looking at a printed calendar for a given month. The weeks are in rows. Each day is a square on the calendar. You draw a three-by-three square around nine dates. You notice that the sum of these dates … Continue reading

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Yin Yang Circle

Diameter is divided at in the ratio  The two semicircles,  and , divide the circular region into an upper (shaded) region and a lower region. Find the ratio of the area of the upper region to that of the lower … Continue reading

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Shaded Stripes

What fraction of this square region is shaded? Stripes are equal in width, and the figure is drawn to scale. Source: Julia Robinson Mathematics Festival SOLUTION Suppose without loss of generality that the width of the stripes equals 1 unit. … Continue reading

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Geoboard Triangle

The horizontal and vertical distances between adjacent points equal 1 unit. Find the area of triangle . Source: Julia Robinson Mathematics Festival SOLUTION area of triangle  = area of triangle + area of triangle + area of trapezoid = area … Continue reading

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