Final answer:
To find the constant of joint variation, substitute the known values into the equation y = kxz and solve for k. In this case, the constant of variation is 20.
Step-by-step explanation:
In a joint variation, y varies directly with both x and z. The equation to represent joint variation is y = kxz, where k is the constant of variation. Given that y = 30 when x = 1/4 and z = 6, we can solve for k.
To find the constant of variation in a joint variation, we need to first identify the known values and the unknown constant. In this case, we are given that when x = 1/4 and z = 6, y = 30.
Substitute the known values into the equation:
30 = k * (1/4) * 6
Solve for k:
30 = (3/2)k
k = 30 / (3/2)
k = 20
Therefore, the constant of variation is 20.