Which is the area of a circle with circumference of 15.7 units? ( use 3.14 for )

Which is the area of a circle with circumference of 15.7 units? ( use 3.14 for )

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  1. Step-by-step explanation:

    Circumference of the circle= 30π units

    [tex]2\pi \: r = 30\pi[/tex]

    [tex]r = 15 \: units[/tex]

    Area of the circle =

    [tex]\pi {r}^{2} = \pi {15}^{2}[/tex]

    = π225 sq. unit

    =3.14× 225 sq. units

    =706.5 sq units

  2. a) 0,0; 1,1; and 2,2

    step-by-step explanation:

    these have the exact same coordinates, thus they are the correct function.

  3. Formula for circumference= 2πr but since the problem says to use 3.14 for pi, then you can write the equation:

    C=2*3.14*r
    9.42=2*3.14*r
    Divide both sides by 3.14 and you'll get
    3=2r and divide by 2 so
    r=1.5

    then you can substitute 1.5 into circle area formula
    A=3.14*1.5^2
    A=3.14*2.25
    A=7.065 square inches

  4. perimeter = 8[tex]\sqrt{\pi }[/tex]

    Step-by-step explanation:

    We require to calculate the area (A) of the circle

    A = πr² ← r is the radius

    circumference = 4π = 2πr, hence

    2πr = 4π ( divide both sides by 2π )

    r = 2, hence

    A = π × 4 = 4π

    The area of the square is therefore 4π and area = s² ← s is the side length

    s² = 4π ( take the square root of both sides )

    s = [tex]\sqrt{4\pi }[/tex] = 2[tex]\sqrt{\pi }[/tex], hence

    perimeter = 4 × 2[tex]\sqrt{\pi }[/tex] = 8[tex]\sqrt{\pi }[/tex]

  5. Circumference of a circle= 2πr = 15.7
    from this radius r= 15.7/ 2π
    r= 15.7/(2x 3.14)
    r= 15.7/ 6.28 = 2.5
    therefore area = π r^2= π x r x r
    = 3.14 x 2.5 X 2.5 = 19.625 sq units

  6. A = π(r²) --- r is radius

    C = πd --- d is diameter

    First, the circumference must be found. If the circumference is 15.7, plug it in.

    15.7 = πd

    We know what pi is.

    15.7 = 3.14 (d)

    Now, simply divide 3.14 by 15.7 to find the diameter (d). You get 5. Since the radius is half of the diameter, the radius is 2.5. Plug this into the area formula, and plug pi in, too.

    A = 3.14(2.5²) 

    2.5 to the second power is 6.25.

    A = 3.14(6.25)

    Tada! Multiply, and you're left with 19.625!

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