Matrix Rotations (Jump to: Lecture | Video )

Figure 1.

Above we have a triangle graphed on a coordinate plane. Its three points (x, y) are displayed in a vertex matrix.

Matrix multiplication can be used to rotate a figure. To rotate a figure is to move it around a center point.

Figure 2.

Let's rotate triangle ABC 90 degrees counterclockwise.

Figure 3.

Now, we've rotated the triangle.