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

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.

**** 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...

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!

Set up eqns, n=5+2d 5n+10d=4.05 plug one into the other, solve. plug result into either, solve for other.

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

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...

Oh I see, you dropped the decimals... Got it... You guys are my heroes... Now if I could get a book that explains stuff better or an instructor that gives better lectures......