19. The area A of a circle is pi times the radius r squared. Translate into a equation
1 answer:
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Answer:
<u>Option D: A cylinder with a circumference of about 50 units</u>
Step-by-step explanation:
The rest of the question is the attached figure.
The square shown has a perimeter of 32 units. The square is rotated about line k. What shape is created by the rotation and what is the approximate circumference of the base? Circumference of a circle: C = 2πr
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Given: the perimeter of the square = 32
perimeter of a square is four times the length of its side
So, the side length of square = 32/4 = 8 units
The square is rotated about line k.
So, it will form a cylinder with radius 8 units.
Circumference of a circle = 2 π r
Where, r is the radius of the circle.
Circumference of the base is C = 2 π * 8
∴ C = 16π = 16 * 3.14
∴ C = 50.26548 ≈ 50
The shape is created by the rotation is a cylinder with a circumference of about 50 units.
<u>So, the answer option is D.</u>
