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## yeval76 one year ago Cylinder A has a radius of 12 inches and a height of 6 inches. Cylinder B has a volume of 648π. What is the percent change in volume between cylinders A and B? Cylinder B is 50% smaller than cylinder A. Cylinder B is 25% smaller than cylinder A. Cylinder B is 150% bigger than cylinder A. Cylinder B is 200% bigger than cylinder A.

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1. yeval76

@ganeshie8

2. yeval76

@ganeshie8

3. mathstudent55

First, find the volume of cylinder A.

4. mathstudent55

Do you know how to find the volume of a cylinder?

5. yeval76

The volume of cylinder A is 2,712.96

6. mathstudent55

$$\Large V_{cylinder} = \pi r^2 h$$ where r = radius of the base, and h = height of the cuylinder

7. yeval76

Yea so the volume of cylinder A is 2,712.96

8. yeval76

So what do I do now?

9. mathstudent55

Correct. Since the volume of cylinder B is written in terms of pi, you can also write the volume of cylinder A in terms of pi. (In other words, don't multiply pi in the formula.) $$\Large V_{A} = 864 \pi$$ $$\Large V_B = 648 \pi$$ Ok so far?

10. yeval76

Yes mam or sir

11. yeval76

Would you divide Va by Vb and then multiply it by 100...

12. mathstudent55

Now we need the second step of the problem. We need to find the percent change. Look in all choices. Every choice states "Cylinder B is ... than cylinder A." This means we are comparing cylinder B to A.

13. mathstudent55

Here is the formula to calculate percent change: $$percent~change = \dfrac{new~amount - old~amount}{old~amount} \times 100$$ If the percent change is positive, it is an increase. If the percent change is negative, it is a decrease. In this case, since we are comparing cylinder B to cylinder A, then old amount = 864 pi new amount = 648 pi (pi will cancel out in the calculation.)

14. yeval76

So will it be 25% smaller then cylinder A right?

15. mathstudent55

Correct.

16. yeval76

Yayyyy Thank You!!! @mathstudent55

17. mathstudent55

You're welcome.

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