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Sra
Sra asked in Science & MathematicsMathematics · 8 months ago

HELP WITH MATH IM CRYING?

a stone dropped into a pond causes a circular ripple to move outwards the radius of the ripple increasing at the rate of 2m/sec. How fast is the area inside the ripple changing when the radius is 5 meters?

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  • Wayne DeguMan
    Lv 7
    8 months ago

    dr/dt = 2

    Area is πr²

    so, dA/dt = 2πr.dr/dt

    or, dA/dt = 2πr(2) => 4πr

    With r = 5, we have dA/dt = 20π => 62.83 m²/sec

    :)>

  • alex
    Lv 7
    8 months ago

    A = πr^2 , given dr/dt = 2 m/s at r=5

    dA/dt = 2πr(dr/dt)=2π(5)(2)=20π m^2/s

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