Word problem regarding geometry

Question

How many square tiles (20 cm x 20 cm)  are needed to coat the sides and base of a pool which is 10 m long , 6 meters wide and 3 m deep?

Answer 1

 

Base is 10 x 6 = 60

 

Side is 10 x 3 = 30. THere are 2 of them, so 60

 

Front and Back: 2 x 3 x 6 = 36

 

Total surface area is 60 + 60 + 36 = 156 square meters.

 

1 square meter = 100 cm x 100 cm = 10000  cm^2

 

156 square meters = 1,560,000 square centimeters

 

Each tile 20 cm x 20 cm = 400 cm^2

 

1560000 / 400 = 3900 tiles are needed