Answer:
This is the concept of scale factors; The length of the larger figure will be calculated as follows; 
linear scale factor=[length of larger figure]/[length of smaller figure] 
plugging the values in the above formula we get: 
let the length of the larger figure be x; 
thus; 
x/12=4/3 
multiplying both sides by 12 to solve for x we get: 
12*x/12=4/3x12 
x=16 
thus the length of the larger figure is x=16