If you are working in groups to construct triangles and then, in Problem B6, quadrilaterals, discuss the rules you came up with for instances in which three lengths make a triangle and in which four lengths make a quadrilateral.
Sometimes people may be confused about the question of whether or not you can "deform" one triangle into anther one. It helps to build another figure -- use five sides so as not to give away the answers for the quadrilaterals in Problem B6 -- and see how easy it is to push on the sides and angles to form many different pentagons with the same five sides. Then, although the materials may allow a little bit of "wiggle," it becomes clear whether or not you can deform a triangle into a completely different one.
<< back to Part B: Linkage-Strip Constructions