The hall, 12 m long and 8 m wide, was increased in length by 4 m and in width by 2 m.

The hall, 12 m long and 8 m wide, was increased in length by 4 m and in width by 2 m. How many square meters increased the area of the hall.

Let’s find the area of the hall before the increase. We multiply the length by the width.
S = 12 m * 8 m = 96 m².
Let’s find the area of the hall with increased length and width.
S = (12 m + 4 m) * (8 m + 2 m) = 16 m * 10 m = 160 m².
Find the area difference.
160 m² – 96 m² = 64 m².
Answer: the area of the hall was increased by 64 m².