Use the polygon tool to graph the reflection of this rectangle across the x-axis.

Step-by-step explanation:

From the figure attached,

Coordinates of the vertices of the given rectangle ABCD,

A(3, 6), B(12, 6), C(12, 1) and D(3, 1)

Rule for the reflection of a point across x-axis,

(x, y) → (x, -y)

After reflection of the given rectangle across x-axis image points will be,

A(3, 6) → A'(3, -6)

B(12, 6) → B'(12, -6)

C(12, 1) → C'(12, -1)

D(3, 1) → D'(3, -1)

Now we can plot these points on the graph to get the image of rectangle ABCD.