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I have drilled a hole.........

AncientMariner
Well, I did not drill it, but about 50 years ago a colleague produced this question from his book:


"A cylindrical hole six inches long has been drilled straight through the centre of a solid sphere. What is the volume remaining in the sphere?"

Enjoy!

Clive
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  • 0
    There’s a Saturday night challenge, work out the area of a circle by using a quarter of the circumference squared rather than by A = π r² and compare the results.


    Circumference =2 π r


    Quarter Circumference =π r/2


    square of Quarter circumference = r² π²  /4 =r² * 2,468  approx


    Area of circle total =  π r² =r² * 3,14  approx   


    Suggests you lose about a quarter of the volume  in the process of  making it into rectangular planks. which feels quite good to me,



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  • 0
    There’s a Saturday night challenge, work out the area of a circle by using a quarter of the circumference squared rather than by A = π r² and compare the results.


    Circumference =2 π r


    Quarter Circumference =π r/2


    square of Quarter circumference = r² π²  /4 =r² * 2,468  approx


    Area of circle total =  π r² =r² * 3,14  approx   


    Suggests you lose about a quarter of the volume  in the process of  making it into rectangular planks. which feels quite good to me,



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