Why are triangles used in bridges?
Triangles are used in bridges because they evenly distribute weight without changing their proportions. When force is applied on a shape like a rectangle it would flatten out. Before triangles were used in bridges, they were weak and could not be very big. To solve that problem engineers would put a post in the middle of a square and make it more sturdy.
This beam turns he square into two triangles that can each distribute weight evenly. the square is not able to buckle because the middle beam is fastened to the corners of the square. The corners can't move any closer or any farther from each other because the beam keeps them in place. Architects use many triangles in bridges.
What types of triangles
Equilateral triangles are most commonly used in truss bridges, while scalene triangles are commonly used in more modern designs. just about all bridges use right triangles.