Travel posters

This task is about working out a missing dimension of a rectangular shape.
[not drawn to scale]
a)
The bigger photo has been enlarged from the smaller photo. Show how to find the missing dimension (x).
 

  

 

 

  
 
The length of x is __________ cm  

 
 
[not drawn to scale]
 
b)
The bigger photo has been enlarged from the smaller photo. Show how to find the missing dimension (y).
 

 

 

 
 
 
The length of y is __________ cm