If a vertical line is drawn from the vertex of a triangle to its opposite side (or the straight line where the opposite side is located), then the line segment between the vertex and the vertical foot is called the height line of the triangle, which is called height for short.

Obviously, the height of a triangle is a line segment. Because a triangle has three sides, it has three heights.

Draw a vertical line from any point on one side of the parallelogram to the opposite side (or the line where the opposite side is located), and the line segment between this point and the vertical foot is called the height of the parallelogram.

The side where the vertical foot is located is called the base of the parallelogram.

According to the definition, a parallelogram can have countless heights, but only four bases!

The line segment from trapezoid to vertical foot is called the height of trapezoid! The side where the vertical feet are located is called the bottom of the trapezoid.

According to the definition, a trapezoid can have countless heights, but only two bottoms!

Lead a vertical line to the bottom surface, and the line segment between this point and the vertical foot is called the platform height.

It is easy to know from the definition that a platform can have countless heights, but there are only two at the bottom!