### 1. Select the letters that would appear the same after a 180 rotation

```1.
Select the letters that would appear the same after a 180 rotation about the center.
I.
II.
III.
IV.
A.
2.
B.
III only
C.
I and III
D. II and IV
rectangle
B.
equilateral triangle
C.
parallelogram
D. square
C.
40
D. 30
What is the rotational symmetry of a regular nonagon?
A.
4.
I only
Which shape, if rotated 90 , will coincide with itself? (“Coincide” means means there's an exact match between
the set of points, or one shape will lay perfectly on top of the other.)
A.
3.
A
H
R
S
60
B.
45
Look at this gure:
If the gure is rotated a certain number of degrees, the transformed gure will coincide with (overlap) the original.
Which of these cannot be the rotation?
A.
5.
240
B.
120
C.
180
In most computer drawing programs, you can “duplicate and mirror” a
Mirror means re ect the gure across a horizontal or vertical line.
D. 320
gure. Duplicate means make a copy.
Which of these gures, when duplicated and mirrored, will never match the original gure?
A.
isosceles triangle
B.
equilateral triangle
page 1
C.
rectangle
D. parallelogram
6.
A congruence transformation that includes both a re ection and a translation is called “glide symmetry”. For
example:
re ection
+
translation
=
glide symmetry
Glide symmetry is very common in nature and the visual arts. Which of the following shows glide symmetry?
I.
II.
III.
A.
I only
B.
II only
C.
page 2
II and III only
D. I, II and III
7.
A tessellation is a repeating pattern based on congruence transformations. Here are some examples:
I.
II.
III.
Which of the above examples use only translations to make the pattern?
A.
I only
B.
II only
C.
page 3
I and II only
D. II and III only
8.
The image below is a dartboard. It has what is called rotational symmetry.
An image has rotational symmetry if it can be rotated through a certain angle and appear unchanged. Assume A is
the measure of the angle (the smallest number of degrees that shows rotational symmetry) and n = 360=A. If n is a
whole number, then we call the symmetry “n-fold”.
What is the symmetry of the dartboard?
A.
20-fold
B.
12-fold
C.
page 4
10-fold
D. 4-fold
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