Q. How many times smaller is the volume of a cylinder if the diameter is multiplied by 21?
Volume Formula: The volume of a cylinder is given by the formula V=πr2h, where r is the radius and h is the height of the cylinder.
Halving Diameter: If the diameter is halved, then the new diameter is d/2, and the new radius is r/2, since the radius is half of the diameter.
Volume Comparison: We need to compare the volume of the original cylinder with the volume of the new cylinder with the halved diameter. Let's call the original volume V1 and the new volume V2.
Original Volume: The original volume V1 is πr2h.
New Volume Calculation: The new volume V2, with the halved diameter (and thus halved radius), is π(2r)2h=π(4r2)h=(41)πr2h.
Volume Ratio Calculation: To find out how many times smaller the new volume is compared to the original volume, we divide V1 by V2: V2V1=(41)πr2hπr2h.
Simplified Ratio: Simplify the expression: V1/V2=(πr2h)/((1/4)πr2h)=4/1=4.
Final Conclusion: The new volume is 4 times smaller than the original volume when the diameter of the cylinder is halved.
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