Out of the window

Find out how many pieces of hardboard of differing sizes can fit through a rectangular window.
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Problem

I have four rectangular pieces of thin hardboard whose dimensions (in cm) are 55 x 85, 65 x 75, 65 x 85, 90 x 105. Without bending the hardboard, how many of these can I get through an open rectangular window measuring 60 cm x 80 cm?

 

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.