math
posted by sandra .
A varies BC, when b=4,and c=9,a=6
a.find the formulea connecting A,B and C.
b.find A whenn B=3 and C=10
c.find C, if A=20 and B=15

Could you clarify what you mean by "A varies BC" please? I feel there's more to this question than reproduced here.

did you mean
A vavies with BC or A varies directly with BC, if so, then
a. A = kBC
so, 6 = k(4)(9)
k = 6
then A = 6BC
b. A = 6(3)(10) = 180
c. 20 = (6)(15)C
C = ......