Carts and Wheels - Drawing Circles with a Compass

A circle is a perfectly round flat shape where every point on the boundary is at an equal distance from a fixed point in the middle called the center. Visual description: Imagine a dot in the center of a page with a curved line drawn at a constant distance all the way around it.

The Radius ($r$) is the distance from the center of the circle to any point on its boundary. Visual description: In a bicycle wheel, the spokes that connect the center hub to the outer rim represent the radii of the circle.

The Diameter ($d$) is a straight line that passes through the center and joins two points on the boundary. Visual description: The diameter looks like a straight line cutting the circle into two exactly equal halves or semi-circles.

A Compass is a geometric tool used to draw perfect circles. It has two legs: one with a sharp metal pointer and another with a holder for a pencil. Visual description: When drawing, the metal pointer stays fixed at the center while the pencil leg swings around to create the curved boundary.

A Chord is any straight line segment that joins two points on the circle's boundary. Visual description: While a diameter must pass through the center, a chord can be anywhere inside the circle. Note that the diameter is the longest possible chord in a circle.

The size of a circle is determined by the length of its radius. If you increase the distance between the compass needle and the pencil, you will draw a larger circle. Visual description: A circle with a radius of $5\text{ cm}$ will look much bigger than a circle with a radius of $2\text{ cm}$.

Circumference is the total length of the boundary or the 'fence' around the circle. Visual description: If you were to take a piece of string, wrap it once around a circular tin, and then straighten the string out, the length of that string is the circumference.