Box Method - Pythagoras
Height - 13cm
Width - 23.5cm
Length - 34.3cm
Step 1-
23.5² + 34.3² = 1728.74²
H²= 1728.74
Square root = 41.6cm
Step 2-
13² + 41.6² = 1899.56²
H²= 1899.56²
Square root= 43.6cm
An object of 43.6cm will fit into the box through the middle on a diagonal.