Scales and Maps

Finding the actual distance (in km) between two points on a map given the scale.

Gradient of Tangent

Finding the equation of the tangent to a parabola at a particular point. (The average gradient between two points is the vertical difference divided by the horizontal but I didn't say that when illustrating the moving line. I do make amends at the end of the video.)

Di-section Puzzle

This is a puzzle which transforms an equilateral triangle into a square.

Solving a quadratic equation

Sample video of a simple quadratic equation.