Maths homework question query

[littlenicky61]

Just looking for someone who is better at maths than me to double check one of my daughters maths answers as she not 100% sure she got it right .

Question :
A can has a height of 11cm and radius of 3.5cm. The label covers the entire height of the can and the label has a 1cm overlap vertically so that it can be stuck together. Calculate area of label.

I think its the mention of the vertical overhang that has made her question herself so thought I'd check with the Mumsnet mums !

Answer :

Area of label = h x pi x d = 11 x pi x ( 7cm + 1cm ) = 276.46 cm2

Many thanks !

Not quite. The diameter has not increased by 1cm, the circumference has, so you want:
11 x (pi x 7 + 1) = 252.9 sq cm

And a maths question in Unanswered Messages - you made my day (ex-maths teacher, nice to dabble occasionally ).

The way I'm picturing it the vertical overhang bit means the height has increased by 1cm. Using the formula for surface area of a cylinder
I'd do (11+1)X pi X (3.5x2).

I agree with DadDad.

If there's no diagram, it might help her to sketch one quickly so she can see where the over hang is.

But it could easily be what daddaddad says-I'm not sure the question is particularly clear. I'm another germ who likes maths puzzles (I teach maths too).

Wait-it says overlap not overhang-I'm changing my answer to 11+(2x3.3xpi+1)

I think it's the way the question is worded, purple. It isn't particularly clear what it is talking about. It does sound like it should be overhanging the bottom of the tin but that wouldn't make any sense in terms of sticking the label together.

I suppose if it said "vertical overlap" that would be slightly less ambiguous, but it's clear to me, it's like the label on a jam jar, with a height of 11 cm then wrapping all the way round plus another cm so that an overlap exists running vertically down the tin.

Thanks for all your responses sorry only just had chance to read them . Sorry toi it should have been vertical overlap not overhang !! And it said can of baked beans if that changes anything ? Will that change things again or is daddaddad correct with 252.9. Thanks again to you all: )

If you use pi=22/7 then it comes out to a neat 253.

I agree with DadDadDad, but I'd want her to understand why it's 11 x (pi x 7 + 1) so I'd break it down:

The area of the tin surface is h x pi x d

So 11xpix7=241.9

The overlap has nothing to do with the tin itself. It's just a 1 cm rectangle of extra paper attached to the end. So that is h x w

11 x 1= 11

Total area: 241.9 + 11 = 252.9 cm^2

Hi, I have a problem with my math homework also, can anybody help me? More details ask4essay.com/thread/i-need-help-with-my-math-homework/

Ibugor18 if you start your own thread you will probably get replies, but you will need to set the maths problem out in your post rather than just providing a link.