Answer
y=20.6
Work Step by Step
Set the product of the means equal to the product of the extremes and solve for the variable.
$y \times84=12 \times144$
$84y=1728$
$84y\div84=1728\div84$
$y=20.\underset\uparrow57142$
Since the number to the right of the 3rd significant digit is greater than 5, round up.
