Answer :
to be a triangle every side has to be smaller than the other two added together, otherwise it would collapse to a line
100+200<600 -> can't be a triangle
11+14<26 -> can't be a triangle
10+16<30 -> can't be a triangle
41+51>61
41+61>51
51+61>41
-> is a triangle
4)
20+34>27
20+27>34
34+27>20
-> is a triangle
20+34<=60 -> not a triangle
14+20<=34 -> not a triangle
20+34<=54 -> not a triangle
5)
52+70<=122 -> not a triangle
52+70>124
52+124>70
70+124>52
->is a triangle
52+70>11
52+11<70 -> not a triangle
52+16<70 -> not a triangle
100+200<600 -> can't be a triangle
11+14<26 -> can't be a triangle
10+16<30 -> can't be a triangle
41+51>61
41+61>51
51+61>41
-> is a triangle
4)
20+34>27
20+27>34
34+27>20
-> is a triangle
20+34<=60 -> not a triangle
14+20<=34 -> not a triangle
20+34<=54 -> not a triangle
5)
52+70<=122 -> not a triangle
52+70>124
52+124>70
70+124>52
->is a triangle
52+70>11
52+11<70 -> not a triangle
52+16<70 -> not a triangle