Here's why:

* Transverse waves are waves where the oscillations of the medium (or the field, in the case of electromagnetic waves) are perpendicular to the direction of wave propagation.

* Electromagnetic waves consist of oscillating electric and magnetic fields. These fields are perpendicular to each other, and both are perpendicular to the direction of the wave's travel.

Think of it like a rope tied to a post. If you shake the rope up and down, you create a wave that travels horizontally along the rope. The direction of the wave's motion (horizontal) is perpendicular to the direction of the rope's movement (up and down).

Similarly, in an electromagnetic wave, the electric and magnetic fields oscillate perpendicular to the direction the wave is traveling.

Let me know if you would like to know more about electromagnetic waves!