## Parts of the Circle

**Circumference**- Circumference is the distance around the outside of a circle. Another way of describing it is the perimeter of a circle.**Chord**- A chord is a straight line that joins two points on the circumference. these two points can be anywhere on the circumference.**Diameter**- A diameter is a chord that passes through the centre point of the circle. A diameter is the longest possible chord you can draw in the circle.**Radius**- A radius is a line joining the centre of the circle to a point on the circumference. You maybe often see it shortened in drawings to the letter 'R'. For example R50 meaning a radius of 50mm. The plural of radius is radii.

**Arc -**An arc can be any part of the circumference.

**Quadrant -**A quadrant is a quarter of a full circle.**Sector**- A sector is the area of a circle enclosed by two radii and an arc. A quadrant is also a form of sector. An easy way to remember what a sector is, that it looks like slices of pizza.**Segment -**A segment is the area of the circle enclosed by a chord and an arc. An easy way to remember what a segment is, that it takes the shape of an orange segment.

**Radius**- A semi-circle is exactly half of a circle. A semi-circle has to contain the diameter of that circle.