Calculate the area of a rectangular plate that is 2.5 m long and 4/5 of its width wide.

1) Find the width of the rectangular plate presented in the condition, determining what is equal to 4/5 of 2.5 meters. To do this, divide 2.5 meters by the denominator of the fraction and multiply by its numerator.

2.5 / 5 * 3 = 0.5 * 4 = 2.

The width of the rectangular plate is 2 meters.

2) Now, using the width value obtained in the previous action, we find what the area of this rectangular plate is equal to. To do this, we multiply its length and width among ourselves.

2.5 * 2 = 5.

The area of the rectangular plate is 5 m2.

Answer: 5 m2.