If you should be interested, 3Blue1Brown has a video primer on complex numbers that includes describing multiplications by i as rotations on the plane, showing

If you should be interested, 3Blue1Brown has a video primer on complex numbers that includes describing multiplications by i as rotations on the plane, showing why a plane is useful for its representation. I always enjoy videos from that channel. https://www.youtube.com/watch?v=5PcpBw5Hbwo https://www.youtube.com/watch?v=5PcpBw5Hbwo