Question

1. use coordinate notation to describe the rotation. then determine the angle of rotation. assume the rotation is clockwise about the origin.

Explanation:

Step1: Observe key - point movement

Let's take a point, say point A. In the original position, assume its coordinates are \((x_1,y_1)\). After rotation, its new coordinates are \((x_2,y_2)\).

Step2: Analyze the rotation angle

We know that a 90 - degree clock - wise rotation about the origin has the transformation rule \((x,y)\to(y, - x)\). By comparing the positions of corresponding points of the original and rotated figures, we can see that the transformation follows the 90 - degree clock - wise rotation rule. For example, if point A has coordinates \((2,2)\) in the original figure, and in the rotated figure (point \(A'\)), it has coordinates \((2,-2)\) which is consistent with the 90 - degree clock - wise rotation rule about the origin.

Answer:

The angle of rotation is \(90^{\circ}\) clockwise.