Ido not understand how to do this ? ! i need ! i'm in a new math class and school and this counts for part of my grade

Radii go from the center point to the outside edge of the circle

Diameters go from the outside edge of the circle through the center point and to the opposite edge

Chords touch the outside of the circle at 2 points an may or may not go through the center.
(Diameters are special chords that go through the center)

Ibelieve 4mn because it’s like you’re combining them