How To Solve A Quadratic Equation With Origami
To solve x 2  a1 x  a0 set up segments corresponding to the coefficients of the equation
as in the diagram with SA  1 , AB  a1 and BT  a0 .
Draw the line y  1 .
Fold S  (0,1) onto y  1 and make a crease in such a way that the crease passes
through T  (a1 , a0 ) . There will be two possible creases if the equation has two real
roots and no creases if there are no real solutions.
The coordinate of the point where the crease intersects the x-axis is a solution to the
equation.
PCMI 2012
Philip Mallinson