SOLUTION: We use π to calculate area of circles. The ancient Egyptians had a method, documented around 1650 BC in the Rhind Mathematical Papyrus, of calculating the area of a circle wit

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Question 1025560: We use π to calculate area of circles. The ancient Egyptians had a method, documented around 1650 BC in the Rhind Mathematical Papyrus, of calculating the area of a circle without π as we now know it. They took a square with side length equal to the diameter of the circle (Figure 1), trisected each side and removed the corner triangles (Figure 2) and used the remaining octagonal shape (Figure 3) to approximate the area of the circle. Using this method, what would be the calculated area of a circle with diameter 9 units?
https://www.mathcounts.org/sites/default/files/u5328/Egyptian%20Circle.jpg


Answer by ikleyn(52786) About Me  (Show Source):
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We use π to calculate area of circles. The ancient Egyptians had a method, documented around 1650 BC in the
Rhind Mathematical Papyrus, of calculating the area of a circle without π as we now know it.
They took a square with side length equal to the diameter of the circle (Figure 1), trisected each side and
removed the corner triangles (Figure 2) and used the remaining octagonal shape (Figure 3) to approximate
the area of the circle. Using this method, what would be the calculated area of a circle with diameter 9 units?
https://www.mathcounts.org/sites/default/files/u5328/Egyptian%20Circle.jpg
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9%5E2 - 4%2A%28%283%2A3%29%2F2%29 = 81 - 2*9 = 63 sq.units against pi%2A4.5%5E2 = 63.585 sq. inits.