Question

1. rotation 90° clockwise about the origin

Explanation:

Step1: Recall rotation rule

For a 90 - degree clock - wise rotation about the origin, the transformation rule for a point $(x,y)$ is $(x,y)\to(y, - x)$.

Step2: Apply rule to vertices

Assume the vertices of the triangle are $(x_1,y_1),(x_2,y_2),(x_3,y_3)$. After 90 - degree clock - wise rotation, they become $(y_1,-x_1),(y_2,-x_2),(y_3,-x_3)$.

Step3: Plot new points

Plot the new points on the coordinate plane to get the rotated triangle.

Answer:

The new triangle after 90 - degree clock - wise rotation about the origin is obtained by applying the rule $(x,y)\to(y, - x)$ to each vertex of the original triangle and then connecting the new points.