The curved line is called a “circumference.”

The circumference of a circle is the curve which bounds it.

Name a straight line that joins two points in the circumference.

It is called a “chord.”

A chord is a straight line that joins two points of a circumference.

Read six chords in the diagram.

Which two of these chords pass through the centre?

They are called “diameters.”

A diameter is a chord that passes through the centre.

Name a line that joins the centre with a point of the circumference.