RS Aggarwal Solutions for Class 6 Chapter 18 explains definitions of “Circle”. A circle is a shape consisting of all points in a plane that are a given distance from a given point, the centre; equivalently it is the curve traced out by a point that moves in a plane so that its distance from a given point is constant. The circle is a simple closed shape where all points in a plane at a given distance from the centre. The distance around a circle is called the circumference. The distance between the midpoint and the circle border is called the radius. A line segment that joins two points present on a curve is the chord. A line which is drawn across a circle passing through the centre is called the diameter. Bicycle wheel, coin, bangles are the examples of a circle. Some of the main topics related to circles, which are talked about here are interior and exterior of a circle, a diameter of a circle, a chord of a circle, secant of a circle, the circumference of a circle, segments of a circle, semicircle, arc, sector of a circle and concentric circles.