The circumference of the great circle of a hemisphere is 19π inches. Which statements about the hemisphere are true? Check all that apply. (Use 3.14 for π and round answers to the nearest tenth, if necessary. Recall that the formula for the surface area of a hemisphere is S = 3πr2 and the formula for the circumference of the great circle is C = πd.)The radius of the hemisphere is 9.5 inches.The radius of the hemisphere is 19 inches.The surface area of the hemisphere is 3,400.6 square inches.The surface area of the hemisphere is 850.2 square inches.The diameter of the hemisphere is 9.5 inches.The diameter of the hemisphere is 19 inches.
Given the equations of two lines, describe how to determine if the lines are parallel.
Responses may vary but should include some or all of the following information: Find the slope and the y-intercept of each equation. The lines are parallel if their slopes are the same and their y-intercepts are different.
A cylinder and a cone start with the same radius and height. The radius of the cone is then tripled, and the height of the cone is cut in half. The radius of the cylinder stays the same, but the height of the cylinder is doubled. Which change produces a greater increase in volume (i.e., which figure’s volume increases by a larger factor)? Justify your answer. Write “pi” for and “r^2” for .

Reponses may vary but should include some or all of the following information: The original volume of the cone is V= (1/3)pi(r^2)h. Tripling the radius (3r) and halving the height (h/2), we get a new volume of V=(1/3)pi(3r)^2(h/2), or V=(3/2)pi(r^2)h. Thus, the cone’s volume has increased by a factor of (3/2)/(1/3) = 9/2, or 4.5. The original volume of the cylinder is V=pi(r^2)h. Doubling the height, we get a new volume of V=pi(r^2)(2h) = 2pi(r^2)h. Thus, the cylinder’s volume has increased by a factor of 2/1, or 2. Therefore, the changes produced a greater increase in volume in the cone than in the cylinder.
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