# Math homework, HELPPPP`

Discussion in 'The Lounge' started by Capman2k, Jan 28, 2007.

1. ### Capman2k3/4 ton status

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I need to solve this: A circle has a circumference of 48(pi) inches. Find its radius.

So my book has an example of how to figure out a circumference (C=2[pi]R) and I also have an example of how to find the area... But I don't need any of those things, I need the friggin radius....

I'm not sure quite how to set it up, maybe 48(pi)=2(pi)R then solve for R????? em pleh

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24

:d

3. ### 1979jimmy3501/2 ton status

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set it up like you said then solve for r you should get a answer of 24 inches

4. ### Corey 78K51 ton status

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Real simple go out and buy a contractors calculator

5. ### Capman2k3/4 ton status

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Good work, boyz thanks

20 more problems to go, stand by

6. ### cabledawgSecret SquirrelPremium Member

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Actually circumfrence is D x pi. So divide 48 by pi, then divide by 2 (radius is half of the diameter) and the answer should be 7.63 and some change. I use this all the time to find out how far a particular sized tire will travel in one revolution.

7. ### enginenineRegistered Member

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circumference = Pi * 2 * radius. Work backwards

8. ### colbystephens1 ton statusGMOTM Winner

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if you divide 48 (pi) by (pi) you get 48. then divide by two and you've got 24...

9. ### Capman2k3/4 ton status

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**** I hate math... I'm not finishing this assignment. If a math problem makes me swear and want to stab something I think that's enough homework for one day

Kay's change purse has nickels and dimes in it. The number of nickels is 5 more than twice the number of dimes. If the total value of the coins is \$4.05, how many nickels are in the purse?

I've spent 25 minutes on this one and no answer... Maybe I'm a retard, but I follow the example in the book and can't get an answer that could possibly be correct, the closest I've gotten is within .01 of an answer that could even POSSIBLY work...

10. ### Resurrection_Joe1 ton status

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19 Dimes

43 Nickles

405 - (5x5) = 380

2X Nickles = 1X Dimes

380/2 = Amount In Dimes And Nickles

190 = 19 Dimes

190 = 38 Nickels + 5 Nickles

Blah Blah Blah

Hooray for my ****ed up head!

11. ### dhcomp1 ton statusPremium Member

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Set up eqns, n=5+2d
5n+10d=4.05

plug one into the other, solve. plug result into either, solve for other.

12. ### CustomChevy1/2 ton status

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n = nickles
d = dimes

n = 2d + 5

so if

5n + 10d = 405

sub in n
5(2d + 5) + 10d = 405

Compleat Multiplication
10d + 25 + 10d = 405
Subtract 25 from both sides
10d + 10d = 380
total d's
20d = 380
devide both sides by 20
d = 19

So if
n = 2d + 5
n = 2(19) + 5
n = 38 + 5
n = 43

to check
5 * 43 + 19 * 10 = 405
215 + 190 = 405

13. ### Capman2k3/4 ton status

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Hrmmm... I'm not quite getting where y'all are getting 5 and 10 from.

Wouldn't it be .05(2d+5) + .10d putting the values of the coins next to the variable that determines the number of coins? Then you'd multiply the value of each coin by the number of coins to get the amount of money...

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