Step-by-step explanation:
The longest side of a triangle must be less than the sum of the shorter sides.
If 8 and 12 are the shorter sides, and c is the longest side, then:
c < 8 + 12
c < 20
If c and 8 are the shorter sides, and 12 is the longest side then:
12 < c + 8
4 < c
The range of possible lengths for the third side is:
4 < c < 20
