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Math Help - Area of a Sector

  1. #1
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    Area of a Sector

    Find the area of a sector of a circle of radius 3cm formed by an angle of 60 degrees. Round answer to two decimal places.

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  2. #2
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    the area of a sector is 1/2 *r^2* a in radians.
    pi radians=180 deagrees -> pi/3 rad=60 degrees.
    so S=(3^2*pi/3)/2=1.5pi
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  3. #3
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    To find the area of a sector of a circle:

     \frac{\theta_{\deg}}{360} \cdot A

    Area of a circle is:

    A = \pi r^2

    If you want to do it using radians like Tom1234 suggested:

    Here's how you convert from radians to degrees and vice versa:

    \frac{\theta_{\deg}}{180} = \frac{\theta_{\text{rad}}}{\pi}

    Then:

    \frac{\theta_{\text{rad}}}{2\pi} \cdot \pi r^2 = \frac{\theta_{\text{rad}}}{2}\cdot r^2
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  4. #4
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    ok

    Wonderful job!
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