Draw a picture to explain the definition of projection in high school mathematics space geometry. Thank you very much.

[Projection of a point on a plane]? A vertical line drawn from a point to a plane is called the projection of this point on this plane.

As shown in the figure, AA'⊥ plane M, A' is the vertical foot, and A' is the projection of point A on plane M.

Similarly, if BB'⊥ planes M and B' are both on M, then the projection of B on M is B'.

Obviously, the projection of point C on the plane is point C itself.

[Diagonal projection on the plane, diagonal projection on the plane]? A straight line intersects a plane obliquely, and the intersection point is called oblique foot.

Draw a vertical line on the plane where any point on the diagonal is inclined outward enough, and the straight line passing through the vertical foot and the inclined foot is called the projection of the diagonal on this plane; The line segment between vertical foot and inclined foot is called the projection of diagonal line segment from this point to this plane.

As shown in the figure, the projection of straight line AC on plane M is straight line A'C (point C is on plane M), and the projection of line segment AC on plane M is line segment A 'c. ..

Obviously, the projection of line segment AB on plane M is line segment A' b';

The projection of plane perpendicular AA' on plane M is a point, that is, the vertical foot A', and the projection of vertical line segment is also a point, that is, the vertical foot of vertical line segment.