Malcolm Simmons, Peter Cope, Angle and Rotation: Effects of Different Types of Feedback on the Quality of Response, Educational Studies in Mathematics, Vol. 24, No. 2 (1993), pp. 163-176 ...

Lines and angles Horizontal and vertical lines Learn how to identify different types of lines, including vertical, horizontal, parallel and perpendicular.

Learn about angles in triangles and quadrilaterals with this BBC Bitesize Maths article. For students between the ages of 11 and 14.