If a letter has reflection symmetry, we can draw a straight line through the middle of the letter and both sides of the line will look the same. If a letter has rotational symmetry, we can rotate the letter by less than 360^(∘) without changing its appearance.
See solution.
Practice makes perfect
If a letter has reflection symmetry, we can draw a straight line through the middle of the letter and both sides of the line will look the same. Let's illustrate with the letter A.
We see that A has reflection symmetry. But does it have rotational symmetry? If a letter has rotational symmetry, we can rotate the letter by less than 360^(∘) without changing its appearance. Let's try this with the letter A using 90^(∘), 180^(∘), and 270^(∘).
Notice that we could try every possible angles between 0^(∘) and 360^(∘) but it will never map onto itself until we reach 360^(∘). We can conclude that the letter A only has reflection symmetry which means it should go into the left circle but not in the right.
By repeating this process for all letters, we can complete the Venn diagram. Notice that if a letter has neither reflection symmetry, nor rotation symmetry, it goes outside of the circles.
