3, 2, and 1 can be the sides of a triangle because 3 plus 2 is greater than 1.
There are two requirements which 3 numbers must meet in order to
be the sides of a triangle.
1. smallest side + largest side > middle side
2. smallest side + middle side > largest side
Checking 1: 1 + 3 > 2
4 > 2
True, so it does meet the first requirement.
Checking 2: 1 + 2 > 3
3 > 3
False, it does not meet the second requirement,
so the three 3, 2, and 1 cannot be the sides of
a triangle.
Edwin
