Is triangular base more stable than rectangular base?

Question

Is there any thoery/ facts to show that triangular base is more stable?

Since triangular base is more stable, why does the shopping trolley has a rectangular base (or maybe trapezium)?

Answer 1

A three legged pedestal is more stable than a four legged pedestal because three points define a plane and four points define a three dimensional space in any real world situation (one where absolute precision is not possible)
Any rocking (instability) will be (by definition) movement into that third dimension.

addendum:
A shopping trolley (are you in Britain? I am in Canada.) I assume is a shopping cart.
A shopping cart is a compromise between stability, carrying capacity, ease of manoeuvrability and nesting capability (so the space that unused carts take up can be minimized).

Answer 2

For a base that is the same dimension corner to corner, the rectangular (square) base would be most stable, HOWEVER, fact is, a triangular base will always have ALL 3 points in contact when it is sitting down. The rectangular or square base may have only 2 points firmly in contact when sitting down. The other opposite corners may rock back and forth. Providing the base is of ample size, bet on the triangular base.

Answer 3

With todays space geometry teories , triange is the most sapble shape. 3 poins are enough to define a plane and only one plane can contain that 3 points. If you are using rectangular base it has 4 poins and 4 points define 4 planes. Which is more stable, you have a 1/4 chance to find your disered plane in rectangular base. But its 100% proboble you'll find ypour triangular base because it has only one plane. This was the space geometric solution. Here comes other aspects. For examle have a rigit body in a shape of triangular 4 sided. It has most perfect inner force - streess ratios acoording to the statics. You can apply force to any corner and you'll get that same force from each corners. There is no other simple body like that. Other boides that have his ability always can be simplifed to 4sided triangular prsizms. You can see triangular cristilization in the moleculear base. Most satble crystal forms got triangular formations. Soo triange herself a mirical.. =))

Answer 4

The stability of a body does not depend upon shape of the base, it may be triangle, quadilateral, pentagon , hexagon, or a circle. What metters is where is the C.G(center of gravity) located in respect to the base and how does it move when the body is tiltted. Till the C.G passes through the base the body will not topple. So to get stable structures we generally have large base and low center of gravity. Shape of the base is immaterial.

Answer 5

at robots a triangular base is preferred since it does not require adjustments: all three wheels will always be on ground.
when you have 4 wheels (rectangular base) unbalance could make 1 wheel not touch the ground even on flat surfaces - usually suspensions are used to prevent that.

didn't you never had to put a coin under a table foot so the table will not shake?

Answer 6

If you're talking flat base--none is more stable thanthe other, because they are all at the mercy of the roughness of he surface they are set upon. Stability is only a functio nof the longest measurement relative to the center of gravity.

If you're talking legs, three is the most stable, it can adapt to any surface, and stability is only related to howhig the ceter of gravit is and how offset it is from the center of the legs.

Answer 7

I guess the base of the Eiffel Tower looks both triangular and rectangular.

Answer 8

The most stable base is a circular base.

Answer 9

Look at the pyramids. They have stood up for thousands of yours. What more proof do you need.

Answer 10

triangles are the "strongest" shape.... if u put a bunch together they can hold more weight than rectangles