As we know,
The sum of the lengths of any two sides of a triangle must be greater than the length of the third side.
A. 4, 9, 4
[tex]4 + 9 > 4[/tex]
[tex]9 + 4 > 4[/tex]
[tex]4 + 4 < 9[/tex]
B. 3, 8, 12
[tex]3 + 8 < 12[/tex]
[tex]8 + 12 > 3[/tex]
[tex]12 + 3 > 8[/tex]
C. 8, 8, 9
[tex]8 + 8 > 9[/tex]
[tex]8 + 9 > 8[/tex]
[tex]9 + 8 > 8[/tex]
By observing the above,
the possible side lengths of a triangle are C. 8, 8, 9.
