If a varies bc when b =4,c=6, a=30 find the relationship between a,b,c and a, when b=4 and c=6

Answer 1

a = kbc
30 = k*4*6
k = 5/4

and why do you want to find a when b=4 and c=6, when you just said a=30
You would do well to proofread your postings, especially if you're going to repeat them.