Order of rotational symmetry

kevin8 · Post by **kevin8** » Sat Aug 22, 2009 11:19 am

Please can someone tell me the order of rotational symmetry of an equilateral triangle?

The above is the question no 13 of Tuition for you 11Plus Maths Test 6. The answer given is 1. The answer explains â€œAlthough it has got 3 equal sides, a triangle will only look the same when turned through 360o and returns to its original position. Order of rotational symmetry =1â€

KenR · Post by **KenR** » Sat Aug 22, 2009 12:22 pm

Your son is correct - see wikepadia

An equilateral triangle is the most symmetrical triangle, having 3 lines of reflection and rotational symmetry of order 3 about its center.

I can only assume that Tution for you meant to say "Isosceles"

Twinkle · Post by **Twinkle** » Sat Aug 22, 2009 12:42 pm

Just spoken to DH ( who did Maths at Uni) and looked at Tutor's notes for DS1 and they confirm that your DS is correct.

kevin8 · Post by **kevin8** » Sun Aug 23, 2009 1:01 am

Thank you both.

Kevin8