Points A (-1; -2; 0), B (1; -1; 1), C (0; 1; -2) are given. Find them symmetrical about the coordinate planes.

Points are given: A (-1; -2; 0), B (1; -1; 1), C (0; 1; -2). Let’s find the points symmetric to them with respect to the coordinate planes.

We will have three coordinate planes: XOY, XOZ, YOZ.

In order to write a point symmetric about the axis, we change the values conjugated to the plane to the opposite, and leave the third coordinate unchanged.

1) Regarding XOY:

A ‘(1; 2; 0), B’ (-1; 1; 1), C ‘(0; -1; 2).

2) Regarding XOZ:

a ‘(1; -2; 0), B’ (-1; -1; -1), C ‘(0; 1; 2).

3) Regarding YOZ:

A ‘(-1; 2; 0), B’ (1; 1; -1), C ‘(0; -1; 2).