The rectangle has a length of 42dm and a width of 1.5m. The length of this rectangle has been increased by 80 cm

The rectangle has a length of 42dm and a width of 1.5m. The length of this rectangle has been increased by 80 cm, and the width has been reduced by 20%. How many square meters has the area of this rectangle decreased or increased?

We convert all the values of the dimensions of the rectangle into one value.

42 dm = 4.2 meters.

80 cm = 0.8 meters.

Find the starting area of the rectangle.

We multiply its width by its length.

4.2 * 1.5 = 6.3 m2

Find the new length and width.

4.2 + 0.8 = 5 meters (new rectangle length).

100% – 20% = 80%.

1.5 * 80% / 100% = 1.5 * 0.8 = 1.2 m (new rectangle width).

We find a new area.

5 * 1.2 = 6 m2

Find the area difference.

6.3 – 6 = 0.3 m2

Answer: The area of the rectangle has decreased by 0.3 m2