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**kcleigh2****Member**- Registered: 2005-11-24
- Posts: 13

please help me again, thanks its just im really stuck.

1) in each of the following calculations, give your answer in STANDARD FROM TO FOUR SIGNIFICANT FIGURES.

a)148 200*2 531 000*583.2

b)0.0000731*0.0002859*0.03756

c)5.9*18.6*291.7

------------------

515 284

d)3.65*258

thanks i know you must think in thick thanks for helping though.

2)calculate the volume of a cuboid, giving your answwer in STANDARD FORM TO FOUR DECIMAL PLACES.

THE BACK, SIDE LINE IS 0.000 002 56m

THE FRONT SIDE LINE IS 0.000 000 14m

THE BOTTOM LINE IS 0.000 275m

3)the staff car park at a hospital is cirular and of area 715 square metres. how far is it across the car park TO THE NEAREST METRE.?

4)a storage container is in the shape of a hemisphere. it can contain 550 cubic metres of liquid when it is full.

how far is it across the ontainer TO ONE DECIMAL PLACE.

thanks again for this help.

i am really really really rubbish at maths lol lol lol lol lol lol lol lol lol lol lol lol

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,534

Standard form means to write the number in two parts: a) just the digits (with the decimal point after the first digit), followed by b) how many powers of 10 you need to multiply it by to have the decimal point where it should be (ie how many places to move the decimal point).

Example: 125. would be written as 1.25 × 10[sup]2[/sup]

Just think "how many places do I move the decimal point?" in this case it moved by 2 places.

So:

a) 148 200*2 531 000*583.2 = 218754937440000. = 2.18754937440000 × 10[sup]14[/sup]

2) to calculate the volume of a cuboid just multiply width by height by length. I will do this using standard form as I go:

0.000 002 56m = 2.56×10[sup]-6[/sup]

0.000 000 14m = 1.4×10[sup]-7[/sup]

0.000 275m = 2.75×10[sup]-4[/sup]

To multiply them together. you can just multiply the "digits" parts together, and then work out the powers of 10 by adding them, like this:

2.56×10[sup]-6[/sup] × 1.4×10[sup]-7[/sup] × 2.75×10[sup]-4[/sup] =

2.56×1.4×2.75 × 10[sup]-6[/sup]×10[sup]-7[/sup]×10[sup]-4[/sup] = 9.856×10[sup]-17[/sup]

(to work out the "-17", I just added the "-6", "-7" and "-4")

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**kcleigh2****Member**- Registered: 2005-11-24
- Posts: 13

sorry i am so stupid i dont under stand that please could you put it in simplair form thanks

SORRY!!!

i am really really really rubbish at maths lol lol lol lol lol lol lol lol lol lol lol lol

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,534

OK, maybe you should read this page:Index Notation - Powers of 10

And I have put down some of what we tackled here on this page: Scientific Notation

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,562

For #4, you need to know the volume of a sphere, or half of one.

The volume of a sphere is about 52% of the cube it just fits into.

I would have thought it was more like 70%, but I was wrong

**igloo** **myrtilles** **fourmis**

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**luca-deltodesco****Member**- Registered: 2006-05-05
- Posts: 1,470

John E. Franklin wrote:

For #4, you need to know the volume of a sphere, or half of one.

The volume of a sphere is about 52% of the cube it just fits into.

I would have thought it was more like 70%, but I was wrong

well if youre allowed a calculator, you can calculate 4 as

*Last edited by luca-deltodesco (2006-06-19 07:58:15)*

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