Please help me with this just type in the answers that apply

All answers could be B, C and D

Step-by-step explanation:

According to the triangle inequality theorem, the combined length of two sides of a triangle cannot exceed the length of the third side. so:

13+8=21

Which means the sides that are less are A, B, C and D

Now A is smaller terms, if we try to use this to apply to a different way:

8+5=13

13=13

This means that the combined terms are NOT as small as the third side, and therefore this length cannot work. Therefore, the only ones left are lengths B, C and D