Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

I trying to scale object up and back down, I can only use a scale factor to alter the size. I am currently scaling upwards by 1.2.

How do I calculate the scale factor I need to return the object to its' original 100%?

share|improve this question
Ratio and proportion. If object a is twice as large as object b, then object b is half the size of object a. If object a is $1.2$ times the size of object b, then ______. (fill in the blank) –  Guess who it is. Oct 10 '11 at 9:44
object a is 5/6 the size of object a? –  Rob Oct 10 '11 at 10:10
"Object b is...", you mean. That's basically it; reciprocate the scale factor you once used to undo the scaling. –  Guess who it is. Oct 10 '11 at 10:12
sorry yes object b, ok thanks, i think i get it :) –  Rob Oct 10 '11 at 10:14

1 Answer 1

up vote 1 down vote accepted

To settle this question: we always have the relation that if some object B is $p$ times larger than object A, then we can also say that object A is $\frac1{p}$ times the size of object B. In the OP's case, to undo the $\frac65 \times$ scale-up, a multiplication by $1/(6/5)=\frac56$ is needed.

share|improve this answer
I have a question: The way you are doing this problem... Do you use Dimensional Analysis???? –  user52695 Dec 11 '12 at 21:34
You could call it that, yes. –  Guess who it is. Jan 16 '13 at 17:32

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.