Answer:
38.) 1
39.) 27
40.) 216
41.) 25
42.) 30
38) 1 x 1 x 1 = 1
39) 3 x 3 x 3 =27
40) 6 x 6 x 6 = 216
41) 25 unit squares in the next figure after the 4x4 one
42) She saves $30 each week
I hope this helps with what you are doing! :-)