How can I insert 4 arithmetic means between √2 and 12/√2?

How do I incorporate fractions and roots into sequences?

√2,_,_,_,_,12√2

Do it the same way you would with "nice" numbers

term1 = a = √2
term6 = a + 5d = 12√2

√2 + 5d = 12√2
d = (11/5)√2

so the sequence is:
√2 , 16/5√2, 27/5√2 , 38/5√2, 49/5√2, 60/5√2
= √2 , 16/5√2, 27/5√2 , 38/5√2, 49/5√2, 12√2