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uhhhg! i really dont understand the following questions about Area....!! watch

1. Hi
thanks for looking - i have spend the last couple hours looking at this and have finally given in and have asked for some advice - my mum was completely stumped and so am i! so here goes.

question 1)
A tin of diameter 7 cm and height 12 cm has a label around it.

The label is glued together using a 1 cm overlap.

There is a 1 cm gap between the label and the top and bottom of the tin.

Find the length and height of the label.
[4 marks]

QUestions 2:
A large carton contains 4 litres of orange juice.

Cylindrical glasses of height 10 cm and radius 3 cm are to be filled from the carton.

How many glasses can be filled?

Question 3:

The silver bar is 15cm. The bar is melted down and the silver is made into a cuboid. The base of the cuboid is 10cm by 10cm.
What is the height of the cuboid (wtf - how do i work that out)

Many thanks =))
I will +rep if you can help me to get that awnser(s)
KingJ xD
2. 1. Circumference = 2pir = 7 X 3.14 = 22 (21. 98 rounded up)

22+1 = 23 = length 12 - 2 = 10 = height

2. pir^2 = 3.14 X 9 = 28.26 28.26 X 10 = 282.6

4000/282.6 = 14.15 so.... 14.

I hope this is right If you want me to explain then reply.
3. Q1

Length is found by doing π x diameter and then add 2cm for the 1cm overlap

Height is 12cm but has 1cm gap either side so therefore 10cm
4. wow - thanks alot... + rep to you both =>
Q1

Length is found by doing π x diameter and then add 2cm for the 1cm overlap

Height is 12cm but has 1cm gap either side so therefore 10cm
Why would you add 2cm? It's only an overlap of 1cm, so its +1cm
6. (Original post by 2710)
Why would you add 2cm? It's only an overlap of 1cm, so its +1cm
2 x +1cm = 2cm... im not really sure.
7. Added another question =) for all those interested... lol xD
8. (Original post by KingJ)
Question 3:
The silver bar is 15cm. The bar is melted down and the silver is made into a cuboid. The base of the cuboid is 10cm by 10cm.
What is the height of the cuboid (wtf - how do i work that out)
You need to know all the dimensions of this silver bar, then work out its volume.
Q1

Length is found by doing π x diameter and then add 2cm for the 1cm overlap
No, just add 1cm - we only undercounted once.
10. (Original post by generalebriety)
No, just add 1cm - we only undercounted once.
ok MY bad... im just hopeless at GCSE maths. ... well volume at least.
11. Ahhha - lol just updated the post
STUPID ME ! lol xD
12. (Original post by KingJ)
Hi
thanks for looking - i have spend the last couple hours looking at this and have finally given in and have asked for some advice - my mum was completely stumped and so am i! so here goes.

question 1)
A tin of diameter 7 cm and height 12 cm has a label around it.

The label is glued together using a 1 cm overlap.

There is a 1 cm gap between the label and the top and bottom of the tin.

Find the length and height of the label.
[4 marks]

QUestions 2:
A large carton contains 4 litres of orange juice.

Cylindrical glasses of height 10 cm and radius 3 cm are to be filled from the carton.

How many glasses can be filled?

Question 3:

The silver bar is 15cm. The bar is melted down and the silver is made into a cuboid. The base of the cuboid is 10cm by 10cm.
What is the height of the cuboid (wtf - how do i work that out)

Many thanks =))
I will +rep if you can help me to get that awnser(s)
KingJ xD
For question 3, you firstly need to work out the volume of the silver bar (Trapezium formula is 0.5(a+b)h, and times this answer by the length so for this question the volume is 420 cubic centimetres.

Then you use the formula to work out the volume of a cube, but instead you rearrange it in order to get the height (Volume=length x width x height, so height would be: Volume/(Length x Width). So Height would then be 420/100=4.2cm.

You do this method because you know that the volume of the bar will NEVER CHANGE! So the volumes are able to equate and equal.
Hope this helps!

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Updated: February 3, 2010
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