Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

i have following question suppose we have some AB length and have turned it by 90 angle about some arbitrary o point lies on the AB length.after turning AB maps some A'B' length.we should find distances between A and B' if AA'=4 and BB'=10 please help

share|cite|improve this question
up vote 1 down vote accepted

If you rotate the length around a point $O$ on $AB$, then distances are preserved, so $A'O=AO$ and $B'O=BO$. So $\triangle AOA'$ and $\triangle BOB'$ are isosceles right triangles. If $BB'=10$, then the legs of $\triangle BOB'$ have length $10/\sqrt{2}$, and similarly the legs of $\triangle AOA'$ have length $4/\sqrt{2}$. So you then have the length of the legs of $\triangle AOB'$, and you can use the pythagorean theorem to find the distance $AB'$.

share|cite|improve this answer
thank you very much @yunone – dato datuashvili May 29 '11 at 6:50
Glad to help. ${}$ – yunone May 29 '11 at 6:51

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.