Answer

Geometric modelling commands

(a) Scaling: Scaling changes the size of a geometric model. For scale factors $S_x,S_y,S_z$ along the three coordinate axes,
$$x'=S_xx,\qquad y'=S_yy,\qquad z'=S_zz.$$
If all scale factors are equal, uniform scaling is obtained; otherwise the model is stretched differently along different axes.

(b) Mirror: Mirroring produces a reflected copy of the geometry about a specified mirror plane/axis. For example, reflection about the $YZ$ plane gives
$$x'=-x,\qquad y'=y,\qquad z'=z.$$
It is useful for creating symmetric features and opposite-hand components.

(c) Rotation: Rotation turns the model through a specified angle about an axis. For rotation through angle $\theta$ about the $Z$-axis,
$$x'=x\cos\theta-y\sin\theta,$$
$$y'=x\sin\theta+y\cos\theta,$$
$$z'=z.$$
Rotation is used to position geometry and create circular or repeated features.