Data
Swimming pool A Swimming pool B
20 yards long 40 yards long
10 yards width 20 yards width
Area of a rectangle
Area = length x width
Substitution
Area A = 20 x 10 Area B = 40 x 20
Simplification
Area A = 200 yards 2 Area B = 800 yards 2
Proportion
Area B/A = 800 / 200
Result
Area B/A = 4
The area of Pool B is four times the area of Pool A.