What makes the Eiffel Tower rigid?

Answer 1

In geometry, the triangle form is the most rigid. The length of the sides define the shape of the triangle and anything made of triangles will maintain that rigidity.

Looking at the Eiffel Tower you will notice that the whole structure is composed of metal beams meeting to form triangles. The metal beams themselves are made of smaller triangle structures.

Answer 2

Triangles sustain the load that's put onto it.

Answer 3

Because the strongest shape is a triangle people built the eiffel out of triangles which makes it stronger