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Work out the volume of cylinder B

Work out the volume of cylinder B-example-1
User Gmr
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1 Answer

24 votes
24 votes

Answer:

720cm³

Explanation:

Volume of a cylinder is given by Base Area (A) x Height (h)

or V = Ah

Volume of cylinder A = 18 x 5 = 90 cm³

Base Area A = πr² where r is the radius of the base

For cylinder A, if radius = rₐ

Area = π x (rₐ)² = 18

We can see that cylinder B has twice the height of cylinder A. That means cylinder B radius is twice the radius of cylinder A

So radius of cylinder B = 2 x rₐ = 2rₐ

Base Area of Cylinder B = π x (2rₐ)² = 4π(rₐ)² = 4 x Base Area of cylinder A = 4 x 18 = 72

So while the heights are in the ration 1:2, the base areas are in the ratio 1:4 because the areas are directly proportional to the square of the radius

Hence Volume of Cylinder B = 72 x 10 = 720 cm³

Another way to look at this is that the volume of cylinder B = 8 (2 x 2 x2) times the volume of cylinder A = 8 x 90 = 720cm³

User WildWezyr
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