Why are triangles the shape used to make umbrellas? What's another example of an item made from triangular pieces of fabric. Why are triangles used in this construction?

Question

rational · Answer

If I give you lengths of sides, can you figure out the angles in a polygon ?

rational · Answer

consider two examples :
1)  6,6,6
2) 8,8,8,8

rational · Answer

can you figure out what kind of shapes are these and the angles in them ?

anonymous · Answer

um? triangles?

campbell_st · Answer

well I would have thought that the panels of an umbrella are sectors.

anonymous · Answer

but what does that mean

rational · Answer

read the first reply : https://in.answers.yahoo.com/question/index?qid=20070917042651AAuHwBT

jack1 · Answer

triangles are one of the most strongest geometric shapes...?