Home » Past Questions » Mathematics » The area of a circle if \(154\)cm\(^2\). Find its circumference. (Take \(\pi = \frac{22}{7}\))...

The area of a circle if \(154\)cm\(^2\). Find its circumference. (Take \(\pi = \frac{22}{7}\))...



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  • Area of a circle=πr^2. And we have the area to be 154cm^2.
    :.154=22/7 X r^2.
    1078=22r^2
    49=r^2
    r=7.
    Perimeter/circumference of a circle= 2πr
    Circumference= 2 X 22/7 X 7 =44cm

  • (pi)r^2=area of cirle
    (22/7)r^2=154
    r^2=(154*7)/22
    r^2=49
    r=7cm.
    circumference of circle =2(pi)r
    circumference of circle =2*(22/7)*7
    circumference of circle =44cm

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  • Area=pie× radius^2
    Where area=154cm^2
    Therefore
    154=22/7×radius^2
    49=radius^2
    Radius=7

    Cicumference=2pie×Radius
    (Radius=7)
    Circumference =2×22/7×7
    Circumference =44cm