# Shapes

• Mar 3rd 2008, 06:33 PM
Need-Help
Shapes
Okay I was wondering if anyone could help me out with this one:

Which of these polygons always have reflectional symmetry?

A. Parrallelograms and rectangles
B. Parrallelograms and trapezoids
C. Rectangles and trapezoids
D. None of the above

I am not sure I think it is A but want to know if my answer is wrong or correct.
• Mar 4th 2008, 05:53 AM
earboth
Quote:

Originally Posted by Need-Help
Okay I was wondering if anyone could help me out with this one:

Which of these polygons always have reflectional symmetry?

A. Parrallelograms and rectangles
B. Parrallelograms and trapezoids
C. Rectangles and trapezoids
D. None of the above

I am not sure I think it is A but want to know if my answer is wrong or correct.

Parallelograms are allways symmetric about a point (= midpoint of the diagonals) and rectangles are a special form of parallelograms and therefore they are symmetric about a point too. Additionally they are symmetric about the mid-parallels, that means they are symmetric about two different axes.

Trapezoids generally are not symmetric.