Answer:
given a triangle with sides A, B and C the sum of the lengths of any two sides of a triangle must be greater than the third side:
1. A+B>C
2. B+C>A
3. A+C>B
Thus given two sides of A=9 and B=12 C can be:
12−9<C<12+9
C range 5<C<11
Hope this helps you!
