Answer:
1,025cm
Explanation:
According to the Pythagoras theorem:
a^2 + b^2 = c^2
a^2 = (Length of one side of square 3)^2
As, the are of a square = length of one side of the square^2,
then a^2 = area of square 3 = 80cm^2
and b^2 = area of square 2 = 100cm^2
Then, c^2 = a^2 + b^2 = 80 + 100 = 180cm^2
as c^2 ia also equal to the area of square 1,
Area of square 1 = 180cm^2