Question

Joint variation

Answer 1

@ganeshie8 @hartnn @Loser66

Answer 2

If a variable z is jointly proportional to a set of variable x and y, the z = kxy, where k is the constant of proportionality.

Answer 3

we are given
x=4,y=4,z=4
plug them in
z = kxy and find the value of k

Answer 4

4=k*4*4
4=k*16
Here is the way it wants it submitted @hartnn

Answer 5

you started with
****
4=k*4*4
4=k*16
*****

continue: solve for k to get
k= 4/16 = ¼

now use the "direct variation" equation hartnn posted up above:
z = k x y
and replace k with its value ¼
z = ¼ x y
or
z = x y/4

that is what they expect

Answer 6

yup, they wanted equation in x,y,z
for which you needed to calculate k
and then use z=kxy

Answer 7

Thanks!