Triangles are an ideal shape for bridges because they provide structural stability and distribute weight evenly. NS 7 Science Grade 7 (2020) Learners will test the strength and efficiency of shapes and materials used in construction. You may have heard people say that a triangle is a strong shape. In. When you look at bridges, towers, or even simple roof trusses, you might notice a common shape— the triangle. Participants explore the reasons behind the preference for triangular shapes in truss designs, the feasibility of combining different shapes, and the historical. From bridges and skyscrapers to trusses and roof supports, triangles are a fundamental component of strong structures. This isn't just a fun fact—it's a fundamental concept that engineers, architects, and builders have relied on for thousands of years.