Answer: 257.143 square centimeter (approx)
Step-by-step explanation:
Here, Three plates are stored in an L-shaped drawer, as shown so that they fit snuggly inside, with no spaces between the edges of the drawer and the plates.
Therefore,
Total area of L- shaped drawer which is not covered by these plates = Total covered area of the L-shaped drawer - Total area of three plates.
Since, the total area of L-shaped drawer= area of square of side 20 cm+ area of rectangle of length 40 and breadth 20. ( by the given diagram)
Thus, the total area of L-shaped drawer= 
= 400+800
=1200 square cm
Here, the shape of plates are circular and having the radius of 10 cm. ( by the given diagram)
Therefore area of three circular plates = 
=
square cm
Total area of L- shaped drawer which is not covered by these plates =
=257.142857143≈ 257.143 square cm.