do i use the washer or shell method to get the area

[calcnoob145]

this is one of the last problems i'm having difficulty with and i'm not sure which formula to use i tried both but didnt get the right answer

 

[MarkFL]

You use neither the washer or shell methods, as these apply to solids of revolution.

You are told the arbitrary slide is a square...can you state the volume of this slice?

 

[Deleted member 4993]

this is one of the last problems i'm having difficulty with and i'm not sure which formula to use i tried both but didnt get the right answer
View attachment 2802

Like Mark suggested above, the disk or washer method works where the cross-section of solids are circular (result of revolution around an axis). In your case, those won't work because your cross-sections are squares,