Let's understand the general concept behind the area of a square.
We all know the formula for the area of a square is base x-height.
Now let’s do a quick paper cutting work on a perfect square.
Well! now, let's get enter into the concept...
In a perfect square both the base and height (sides) are equal.

Now, have a look at the picture, here we have provided a perfect square.
Now, have a look at the above picture here we provided a perfect square.
Similarly,

IMG 20210925 204119
And let’s cut it diagonally into two equal right angle triangles.
Now we know the area of a triangle is 1/2 x base x height.
Here we have two equal right-angle triangles if we add the area of both the triangles we are going to get the total area of the square

IMG 20210925 204150
So logically two times of the area of triangles will going to give the area of the given square.
Here we can see, one of the ways to understand that, how to find the area of squares using triangles.
But look at the picture above in this case,
The area of a square is always defined in terms of square units. We know the meaning of square right (a structure, which has four equal lengths of sides).
So simply we can generalize the meaning of unit square.
Like below,
Unit square is nothing but, a square of length of each side as one unit. Now if you talk about the area of a square with in terms of square units.

IMG 20210925 204234
If you look at this picture Now
we can divide the area of the square into four equal square units. Because in this case, the values of base and height of given square is 2cm.
So, if we calculate the area of a square using the given value we are going to get the answer for the area of the given square as 4 square units (2*2).