Which type of symmetry do the platyhelminths show?

Symmetry refers to the correspondence of body parts, in size, shape, and relative position, on opposite sides of a dividing line or distributed around a central point or axis.

Platyhelminthes have dorso-ventrally flattened bodies. Their bodies can be divided into two identical halves through one plane. So, platyhelminths show bilateral symmetry.

In radial symmetry,  the body parts are arranged regularly around a central axis.

In biradial symmetry, the organism can be divided into equal parts, but only in two planes.

In spherical symmetry, the body parts are arranged concentrically around or radiate from the center of the spherical body.