The diameter of the inner circle of the ring is 10 cm, and the diameter of the outer circle is 16 cm. Calculate the area of the part of the ring cut along the two radii with an angle of 60 °

3.14 * (8 * 8-5 * 5) * (60 / 360) = 20.41 square centimeter

The outer radius of a ring is 10cm, the inner radius is four fifths of the outer radius, and the area of the ring is () cm2

Inner circle radius = 10 × 4 / 5 = 8 cm
Area = 10 × 10 × 3.14-8 × 8 × 3.14 = 113.04 square centimeter
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How many kg / m ^ 3 is 15cm ^ 3

15cm^3=15g=0.015kg/m^3
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