The sum of two sides must be equal to or greater than the third side.
4+15 = 19; 4 + 19 = 23; 15 + 19 = 34.
19 is a possible answer.
4 + 15 = 19; 15 + 15 = 30
15 is a possible answer.
4 + 15 = 19; 4 + 13 = 17; 15 + 13 = 28
13 is a possible answer.
4 + 12 = 16; 4 + 15 = 19; 15 + 12 = 27
12 is a possible answer.
4 + 11 = 15; 4 + 15 = 19; 11 + 15 = 26
11 is a possible answer.
15 + 4 = 19; 4 + 4 = 8
4 is NOT a possible answer because 4 + 4 is less than 15.
Hope this helps =)
