The size of most orchestra's will vary depending upon which work(s) is/are being performed. Many composers were quite specific about what instruments would be employed to play their works.
As of 2007 the National Symphony Orchestra of Peru had ninety members.
KBS Symphony Orchestra was created in 1956.
The number of musicians for an orchestra is usually determined by the composer who will specify which instruments and how many of each is necessary to do his/her work justice.
A "symphony" can have many definitions. It can be a musical piece or can signify a musical group. In the former, there are many pieces of music with the word 'symphony' included, not only for orchestra, but for other solo instruments such as the organ or piano. In that context, a 'symphony' could be played just about anywhere. In context of the latter, a symphony orchestra can also play almost anywhere be it a concert hall, a church, the home, outdoors ... anywhere.
It normally is. The composers of the works determine which instruments and how many of each are going to required to perform their pieces.
One or two. Usually one. Actually, if there is a piano, it is a guest artist and not a part of the orchestra. There are no pianos in a symphony orchestra
See the thing is, a band can have as little or as many instruments as preferred. Unless it is like a symphony orchestra when many are needed.
100
There are four stringed instruments used: violin, viola, cell, and bass.
There is 1 triangle in a symphony orchestra and a 2 in a orchestra
A full symphony orchestra could easily have 80 people.
Four