Which parts of △DEF can be determined using only the Law of Cosines?

The length of DE,

Step-by-step explanation:

The law of cosines is applied when  2 sides and the included angle are known.

So here:

DE^2 = 6*2 + 9^2 - 2.6.9cos53.

unless if u could do my questions, if not i wouldn't want to

answer: all of the odd numbers were opened

the first person was the one that was opening all of the lockers. since one is odd, this causes all of the odd number lockers to be opened in the end.