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

enter image description here

This is a practice question to a test I will be taking soon. My conjecture is that it's none of the choices given. I tried reflections about y=x, y-axis, x-axis and it doesn't work. Does anyone agree?

share|cite|improve this question
It seems to be none of the above. – Euler....IS_ALIVE Dec 17 '13 at 9:32
up vote 2 down vote accepted

The correct answer on the test should be $A$.

However, you could make a convincing argument for case $B$, because theoretically, you can do this with two reflections. You first reflect $ABC$ about $y=x$, so it is in the same location as $A'B'C'$. Then you set up a reflection along an axis that goes through the middle of the triangle (a straight line from negative $y$ to positive $x$) to reflect the triangle exactly such that all the points match.

I don't expect that sort of argument to be required.

share|cite|improve this answer

If you use during the transformation odd number of reflection than final triangle would have opposite orientation ie. ABC would go in anti-clockwise order. This rules out II and III.

That the answer is I is already given by Newb.

share|cite|improve this answer

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.