If the radius of a circle is 10 feet, how long is the arc subtended by an angle measuring 81°?
1 answer:
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Answer:
The correct option is;
a. 12 pie cm
Step-by-step explanation:
Cavalieri's principle states that if the cross-sectional area of two or more figures of the same altitude are the same at each level of the figures, then the volumes of the figures are also the same;
Given that the base area of the square based prism and the cylinder are the same, and that the square based prism and the cylinder have equal height of 4 cm, then by Cavalieri's principle, their volumes are the same
The volume of the square based prism = 452 cm³
Therefore, the volume of the cylinder (of equal base area) = 452 cm³
The formula for the volume of square based prism = Area of base × Height
∴ The volume of square based prism, 452 cm³ = Area of base × 4 cm
Which gives;
Area of the base of the square based prism = 452/4 = 113 cm²
The area of the base of the cylinder = The area of the base of the square based prism = 113 cm²
The area of the base of the cylinder, is given by the following equation;
= π×r² = 113 cm²
r = √(113/π) = √35.97 ≈ √36 = 6 cm
The circumference of the base of the cylinder, is given by the following equation
= 2×π×r ≈ 2×π×6 = 12×π cm
The correct option is 12 pie cm.