👉 In geometry, an apothem is a line segment that connects two points on a sphere or other curved surface. It is also known as a chord of the circle. The apothem can be defined in terms of the radius of the sphere and the angle subtended by the chord at the center of the sphere (the apothem). This concept plays a crucial role in various mathematical constructions, such as calculating the volume of a sphere or solving problems involving surface area.