The right angle triangular ground of 6 unit length and 14 unit breadth is half of a rectangular ground of 6 unit length and 14 unit breadth, when the rectangular ground is diagonaly cut into two halves.

So, the area occupied by right angle triangular ground is half of the area occupied by the rectangular ground.

So, let us first calculate area of the rectangular ground of 6 unit length 14 unit breadth and by making it's area half, we can get area of right angle triangular ground.

The ground can be cut along the length in pieces. So each pieces has length of 1 unit and breadth of 14 unit. Let us call these pieces of type A.

There will be 6 number of pieces of type A. So the pieces are of 1unit x 14 unit demension. As there are 6 such type of pieces.

Then we cut each of type A pieces along breadth in pieces. So that each resultant pieces has length of 1 unit and breadth of 1 unit. Let us call these type of pieces of type B.

Now we have total number of unit pieces 6 x 14 unit. The total unit areas to occupy the full rectangular ground is 6 x14.

So the area occupied by rectangular ground is equal to 84 unit.

As the area of right angle triangular ground is half of the rectangular ground so the area of right angle triangular ground= 84/2 = 42