Question

What is j / 6 = 9/10

Answer 1

J/ 6 = 9/10

Cross multiply:
10*j = 6*9
⇒ j= 6*9/10= 5.4

Final answer: j= 5.4~

Answer 2

J/6 = 9/10 is the proportion that we are trying to solve.  Let's use cross products, or multiplying the numerator of one fraction by the denominator of the other fraction, and setting these two numbers equal to one another in an equation.

9 (6) = 10 (j)

When we combine like terms (multiply), we get 

54=10j

We need to divide both sides by 10, to get the variable alone.

j = 5.4