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F3 Maths Area and Volume?

A paper sector VABC of central angle 216° and radius 20 cm is folded into a right circular cone VAB. Find

(a) the curved surface area of the cone VAB

(b) the capacity of the cone VAB

1 個解答

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  • 3 年前
    最愛解答

    a)surface area VAB=area of VABC

    (pi)(20^2)(216/360)=753.9=754cm^2

    b)arc length of sector=circumference VAB=(2)(pi)(20)(216/360)=75.39=75.4cm

    redius of cone VAB=75.4/(2pi)=12cm

    (high of cone)^2+12^2=20^2

    high of cone=16cm

    volume of VAB=(1/3)(pi)(12^2)(16)=2412.7=2410cm^3

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