In thiis activity, you will see the relationship between 2 perpendicular lines and their gradients.[br]For simplicity the equations of the lines you draw have already been given automatically.[br]Use the checkboxes to view or hide values of coordinates, equations and gradient

Drag points A, B for the first line. [br]The line CD has been set to be perpendicular to line AB[br][br]Observe the gradient of line AB, ie. m1 and gradient of line CD ie m2.[br]Note the product of m1 and m2. [br][br]Is the product always the same, no matter how we draw line AB, [br]as long as line CD is perpendicular to AB?