What geometric arrangement characterizes a truss?

• A. A curved, single-member beam
• B. Triangles in one plane
• C. A solid block of concrete
• D. A sheet of plywood with studs

Answer: (B)

Trusses rely on straight members pinned together to form triangular units. That triangular geometry is what gives the structure stiffness: triangles maintain their shape when loaded, so the load is carried mainly as axial forces in the members (compression or tension) rather than bending. Arranging many triangles in one plane creates a rigid, efficient framework using less material than a solid beam or block. A curved single-member beam lacks the discrete triangles that provide that rigidity, a solid block of concrete isn’t a truss, and a sheet of plywood with studs is typical wall framing, not a truss system.