We know the width of the first picture, is 4
we know the ratio from smaller to larger is 1.5:2
thus

solve for "w".
we know the length of the first picture, 6

solve for "L".
Domain is [-1,3)
Range is (-5, 4]
A () bracket means the value IS NOT included, a [] bracket means the value IS included in interval notation.
Answer:
0.328 
Step-by-step explanation:
820mm = 82cm = 0.82m
400mm = 40cm = 0.40m
0.82 x 0.40 = 0.328