Answer:
constant of variation k = 10 when y=12 and x = 1.2 
 
Explanation:
We are given If y varies directly as x, and y is 12 when x is 1.2, what is the constant of variation for this relation? 
 
y = 12 
 
x = 1.2 
 
Constant of variation = k = ? 
 
We know that if y varies directly as x then: 
 
 
 
We need to find k: 
 
 
 
Putting values: 
 
 
 
So, constant of variation k = 10 when y=12 and x = 1.2