Exercise 1 Page 665

Before we begin, recall that a figure in a plane has line symmetry if the figure can be mapped onto itself by a reflection in a line, called a line of symmetry. Let's analyze the given figure.

Now, we will think about if we can draw a line in which the figure can be reflected so it maps onto itself. It does! Let's draw all of the different lines that we can.

We can see that the given figure has $4$ lines of symmetry.