clear unit 17.75 snap off gridstyle grid off axes off unit 1.0 1 style label on coord off filled off font 12 color 0 0 0 fillcolor 128 128 128 let A=[point [-9.0, -4.0]] Style A visible on let B=[point [9.915492957746478, -4.112676056338028]] Style B visible on let C=[point [2.028169014084507, 6.929577464788732]] Style C visible on let segAB=[seg [A B] ] Style segAB visible on label off unit 2 color 255 0 0 let segBC=[seg [B C] ] Style segBC visible on label off unit 2 color 255 0 0 let segAC=[seg [A C] ] Style segAC visible on label off unit 2 color 255 0 0 let D=[pton segAB 0.33879374534623974] Style D visible on unit 2 let line1=[Perpendicular D segAB] Style line1 visible off label off let G=[Intersection segAC line1] Style G visible on unit 2 let line3=[Perpendicular G line1] Style line3 visible off label off let H=[Intersection segBC line3] Style H visible on unit 3 let line4=[Perpendicular H line3] Style line4 visible off label off let I=[Intersection segAB line4] Style I visible on unit 2 let segDG=[seg [D G] ] Style segDG visible on label off unit 3 color 0 51 255 let segGH=[seg [G H] ] Style segGH visible on label off unit 3 color 0 51 255 let segHI=[seg [H I] ] Style segHI visible on label off unit 3 color 0 51 255 let segDI=[seg [D I] ] Style segDI visible on label off unit 3 color 0 0 255 let E=[point [-4.563380281690141, 15.605633802816902]] label E "From Polya's How to Solve It problem 19, page 23. For any triangle is it always possible to draw a square inside the triangle with one side on the triangle base" Style E visible on let F=[point [-4.563380281690141, 14.47887323943662]] label F "and each of the other corners of the square are on the other sides of the triangle?" Style F visible on let J=[point [-4.450704225352113, 13.23943661971831]] label J "Drag D along AB to see rectangles with this type of property. Drag C around to create different triangles." Style J visible on let K=[point [-4.450704225352113, 11.830985915492958]] label K "How would you answer Polya's question and how would you reason about your answer?" Style K visible on let L=[point [-4.169014084507042, 10.140845070422536]] label L "What happens if you drag C far to the left or the right?" Style L visible on