<PRE><B>Question 270921</B>
Square corners, 6 cm on a side, are removed from a 36cm by 42cm piece of cardboard. 
the cardboard is then folded to form an open box.
 What is the surface area of the inside of the box?
:
Find the dimensions of the open box:
(36-12) by (42-12) by 6
24 by 30 by 6 are the dimensions
:
SA = (24*30) + 2(24*6) + 2(30*6)
:
SA = 720 + 2(144) + 2(180)
:
SA = 720 + 288 + 360
:
SA = 1368 sq/cm</PRE>