What is the area of a A4 sheet of paper?

Answer 1

The A series of paper is such that each numbered size of paper has exactly half the area of the previous size. ie A1 is 1/2 the area of A0, A2 is half the area of A1, and so on. Also, A0 has an area of exactly 1 sq m.

Thus A1 has an area of 1/2 that of A0, A2 has an area of (1/2)^2 = 1/4 of A0, An has an area of (1/2)^n of that of A0 = (1/2)^n sq m

1 m = 100 cm

1 sq m = 1 m x 1 m = 100 cm x 100 cm = 10000 sq cm

→ A4 has an area of (1/2)^4 sq m = 1/16 sq m = 0.0625 sq m = 0.0625 x 10000 sq cm = 625 sq cm.