The sum of the length and width of the rectangle is 780 m, and its width is 4 times less than its length. find the area of the rectangle.

To solve this problem, we will use the conditional variables “X” and “Y”, through which we denote the width and length of the rectangle, respectively.

Then, using these problems, we compose a system of equations:

1) X + Y = 780;

2) Y / X = 4.

Solving the system of equations, we get Y = 4X.

Substituting Y into the first equation, we get X + 4X = 780 or 5X = 780 or X = 780/5 = 156 m.

Therefore, Y = 4 x 156 = 624 m.

This means that the area of the rectangle is 624 x 156 = 97344 m ^ 2.

Answer: the area is 97344 m ^ 2.