## anonymous one year ago MEDAL AND FAN PLEASE HELP Cylinder A has a radius of 7 inches and a height of 5 inches. Cylinder B has a volume of 490π. What is the percent change in volume between cylinders A and B? (5 points)

1. anonymous

@Preetha @pooja195

2. anonymous

all you need to to is find the both of the cylinder volumes.

3. anonymous

then divide the first cylinder by the second one, that will give you a number, you then turn that number into a percentage.

4. anonymous

im totally lost here can you tell me how to find the volumes and stuff

5. anonymous

ok

6. anonymous

Cylinder B is 50% smaller than cylinder A. Cylinder B is 75% bigger than cylinder A. Cylinder B is 150% smaller than cylinder A. Cylinder B is 100% bigger than cylinder A.

7. anonymous

$V=\pi r^2h$

8. mathstudent55

Since you were given the volume of cylinder B in terms of pi, calculate the volume of cylinder A also in terms of pi.

9. anonymous

$V=\pi(7)^2(5)=245inches^3$

10. anonymous

$Cylinder B = 490\pi$

11. anonymous

so what would be my final answer? @Mindblast3r

12. mathstudent55

$$\Large V_B = 490 \pi~in.^3$$ $$\Large V_A = \pi r^2 h = \pi (7~in.)^2(5 ~in.) = 245 \pi ~in.^3$$

13. anonymous

what do i do after? @mathstudent55

14. mathstudent55

Since both volumes are shown in terms of pi, and you are interested in the percent difference, you can drop pi from both. What is the percent change from 245 to 490?

15. anonymous

$$\color{blue}{\text{Originally Posted by}}$$ @Mindblast3r $\frac{ CylinderA }{ CylinderB }=\frac{ 245\pi }{ 490\pi }=0.5=50percent$ $$\color{blue}{\text{End of Quote}}$$

16. anonymous

Thank you!!! @Mindblast3r

17. anonymous

I got it thank you both @mathstudent55 @Mindblast3r

18. mathstudent55

@Mindblast3r You need to read the question carefully and make sure you answer the question.

19. anonymous

wait i think

20. anonymous

It would be A right?

21. mathstudent55

22. anonymous

oops no wait.

23. anonymous

oh lol never mind

24. mathstudent55

$$percent~change = \dfrac{new~amount - old~amount}{old~amount} \times 100$$

25. anonymous

Which is it theN? @mathstudent55

26. mathstudent55

Use the formula above to find a percent change. Use 245 as the old amount and 490 as the new amount.

27. anonymous

Its D right????? @mathstudent55

28. anonymous

100 percent

29. mathstudent55

$$percent~change = \dfrac{new~amount - old~amount}{old~amount} \times 100$$ $$percent~change = \dfrac{490 - 245}{245} \times 100$$ $$percent~change = \dfrac{245}{245} \times 100$$ $$percent~change = 1 \times 100$$ percent change = 100%

30. anonymous

THANK YOUUUU

31. mathstudent55

Correct. The answer is that cylinder B is 100% bigger than cylinder A.

32. anonymous

Can you help me with another one? please @mathstudent55

33. mathstudent55

@Mindblast3r Percent change is based on the formula I wrote above. Percent comparisons are tricky. If the question were "what percent of cylinder B's volume is cylinder A?" Then the answer would be 50%. The way the question was asked, though, it requires an answer of 100%. This is why you need to read the problem carefully bec with he given info, the answer could be 50% or 100% or other numbers depending on which way the question is asked.

34. mathstudent55

Sorry, it very late for me. GTG

35. anonymous

ahh i see what they did.