The bisector of a line Student activity Play

The converse of the Pythagorean theorem Student activity Play

The correct perpendicular lines Whiteboard exercise Play

The direction of the Earth's rotation Whiteboard exercise Play

The fence problem Whiteboard exercise Play

The fence problem Student activity Play

The first tangent theorem – perpendicularity Student activity Play

The first tangent theorem – perpendicularity Whiteboard exercise Play

The general form of the equation of a straight line Student activity Play

The gradient of a line Student activity Play

The gradient of a line Whiteboard exercise Play

The gradient of a line perpendicular to the  x-axis Animation Play

The human faces Simulation Play

The pairs of parallel faces in the cube Whiteboard exercise Play

The path of a charge moving perpendicular to the filed lines Animation Play

The perpendicular bisector Student activity Play

The perpendicular bisector Simulation Play

The perpendicular bisector Whiteboard exercise Play

The perpendicular bisector in a circle Animation Play

The perpendicular bisector of a line segment Animation Play

The perpendicular bisector of a line segment – a reminder Student activity Play

The perpendicular bisectors Simulation Play

The points on a straight line Animation Play

The scalar product (1) Class activity Play

The scalar product (2) Whiteboard presentation Play