10
The area of the green square?
square.

Step-by-step explanation:

Now what you have given is not very much accurate. As looking at the figure we know that the outer figure is a square.

The length and width of the square = 10 Units.

So the area of the outer figure can be calculated using the area of a square forlula.

Area of a square = Length X width = 10 X 10 = 100 sq. units.

Now speaking of the green square which is the smaller one.

As per given figure length of smaller square = ½ length of bigger square = 5 unit App.

As it is also a square so length = width = 5

So the area of the green square = 5 X 5 = 25