Answer:
the size of the box is 45"
Step-by-step explanation:
screen measures 36 inches wide by 27 inches high
The diagonal of the box is the size you see on the box.
Lets find the diagonal of the box using pythagorean theorem

Where 'a' is the length and 'b' is the width


Now take square root on both sides
c=45
So the size of the box is 45"