Labelling, drawing and measuring angles Labelling angles and sides

Lines are often shown with letters at the points at either end.

We refer to the line using those two letters. For example, the line below would be called QR.

Often three letters are used to describe an angle.

Two lines, AB and AC meet at point A. AB joins the points A and B. AC joins the points A and C.

The angle between AB and AC is labelled BAC.

The angle can written as BAC or BÂC or ∠BAC.