Radius - GCSE Physics Definition

In physics and mathematics, the term 'radius' refers to the straight line distance from the centre of a circle to its edge or sphere to any point on its surface. Understanding the radius is important because it's used in various equations and calculations, especially when studying topics like circular motion and forces. For example, when you are looking at how planets orbit the Sun, knowing the radius of the orbit, helps figure out the orbital speed of the planet.