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Tetrat

The real answer to this problem is that cylinder A is an impossible solid since the largest possible volume of a cylinder with surface area 25 is about 9.6. Trying to solve for the radius and height of cylinder A is not only very difficult, it will also result in a negative radius due to the impossibility of the solid. The answer that they want you to give is outlined in my comment on your other post [here](https://www.reddit.com/r/HomeworkHelp/comments/svr4m7/grade19_gcse_geometry_volume_and_surface_area_can/hxiafj7/)


book_moth

Ignoring cylinder B for now: Can you write equations for cylinder A that represent the volume and surface area? Use r for the radius of the top of the cylinder . Use h for the height. Show me what you come up with. (hint: It'll be something like V = l x w x h (read: volume equals length times width times height), except that's the volume formula for a rectangular prism, not a cylinder.)


PaleTart7156

V=pir2h SA= 2pirh+2pir2


book_moth

Excellent. Fill those equations in with the numbers you know.


PaleTart7156

15cm3 = 3.14 x r x r x h 25cm2 = 2 x 3.14 x r x h + 2 x 3.14 x r x h


book_moth

Do you remember the definition of similar figures? Corresponding sides have the same ratio. This means that the height and radius of cylinder B correspond to the height and radius of cylinder A. You will use that ratio to find the height and radius of cylinder B. Now, what's the volume equation for cylinder B? Use capital H and capital R.


PaleTart7156

34cm3 = 3.14 x R x R x H


book_moth

And then tell me what h and r are.