1.Many pairs of triangles designed into a building, for example as roof ends, would be congruent, so the roof beam and the top edges of the walls are horizontal.
2.The congruent triangle is used in most of the building that are design to stay in bad conditions and Strong winds for Example the Sydney Bridge.
3.in real life two triangles are rarely exactly congruent. However they are crucial in the construction of large man-made structures. This is because a triangle is the most stable shape and the congruence is needed to create even surfaces.
