The length of the plot rectangle is 5 times its width, and the width is more than 4 m.

The length of the plot rectangle is 5 times its width, and the width is more than 4 m. Prove that the plot area is more than 80m2.

1. Let the width of the section be x m. The length of the section is 5 times the width and is (5 * x) m.

2. Because the section is rectangular, then its area S is equal to the product of its length and width, i.e.

S = (5 * x) * x;

S = 5 * x ^ 2;

3. By the condition of the problem, it is known that the width is more than 4 m, i.e. x> 4.

4. If x = 4, then the area of the plot will be S = 5 * 4 ^ 2 = 80 square meters. But since x> 4, then for any such x the value of S will be greater than 80, p.p.