Math question (High School Algebra level...)

[Hous]

If I have: 1/r = 1/12 how would I solve this for r? I multiplied both sides by 12 and im not sure if this would give me 12r = 144 or not. If so then the answer is r = 12 which is the correct answer. I did this problem completely different from what my book says.

[LoftyDog]

Just cross multiply so you get r x 1 = 1 x 12
r=12

[-Hyperion-]

1/r=1/12

another simple way to look at it........

a/b=c/d

if a=c then b=d.................so r=12

[Hous]

I think I can just flip it when they are both a fraction of 1. I just want confirmation of why or how? If what I did was correct then I know why I can just flip it like you said.

[U.ncleSam]

I think I can just flip it when they are both a fraction of 1. I just want confirmation of why or how? If what I did was correct then I know why I can just flip it like you said.

yes, you can flip it when they are both a fraction of 1.
it's also like cross multiplying. duh.

[Salty]

Easiest way


1/r=1/12
Multiply both sides by r
1= r*(1/12)
Divide both sides by (1/12)
r=1/(1/12)
r=12

[U.ncleSam]

this math question is so easy, a caveman can do this...

[-Hyperion-]

though this procedure was obvious but:

1blankblan1
_blank= bl_blankb= 1(r)=12(1)

12blankblar

just cross em...

[-Hyperion-]

or step by step procedure


1/12=1/r

eliminate 12 keeping the equality:

12(1/12)=12(1/r)
1=12/r

eliminate the denominator r
r(1)=r(12/r)

r=12

[+JC|Arky+]

The answer is always C dude............