Steven
Lv 7
Steven asked in Science & MathematicsMathematics · 1 decade ago

A cylinder has a surface area of 3000sqft. Its length is six times its diameter. How long is the cylinder?

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  • cidyah
    Lv 7
    1 decade ago
    Favorite Answer

    Surface area = 2PI r h + 2 PI r^2 =3000

    h = 12r ( 6 times the diameter means 12 times the radius)

    r = h/12

    Surface area = 2PI (h/12) h + 2PI (h/12)^2 = 3000

    PI h^2 / 6 + PI h^2 / 72 = 3000

    12 PI h^2 / 72 + PI h^2 / 72 = 3000

    13 PI h^2 / 72 = 3000

    13 PI h^2 = (3000)(72)=216 000

    PI h^2 = 16615.3846

    h^2 = 16615.3846 / PI

    h = 128.9 / sqrt(PI)

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