Question

Стороны прямоугольника равны 24 см и 15 см на сколько процентов изменится его площадь если длину каждой стороны уменьшить на 20%

Answer 1

24*15=360 кв.см была площадь
20% от 24 = 4,8 см    24-4,8=19,2 см стала одна сторона
20% от 15 = 3 см  15-3=12 см стала другая сторона
 19,2*12=230,4 кв.см стала площадь прямоугольника  это 64% от первоначальной площади
100-64=36% на 36% уменьшилась площадь.

Answer 2

Calculating the Change in Rectangle's Area

To calculate the change in the rectangle's area when each side is reduced by 20%, we can use the formula for the area of a rectangle: Area = length * width.

Let's calculate the initial area and the area after reducing each side by 20%.

The initial sides of the rectangle are 24 cm and 15 cm.

The formula to calculate the area of a rectangle is: Area = length * width.

Initial Area Calculation

Initial Area = 24 cm * 15 cm Initial Area = 360 square cm

Reducing Each Side by 20%

To calculate the new sides after reducing each side by 20%, we can use the formula: New Length = Original Length - (Original Length * 20%).

New Length = 24 cm - (24 cm * 20%) New Length = 24 cm - 4.8 cm New Length = 19.2 cm

Similarly, for the other side: New Width = 15 cm - (15 cm * 20%) New Width = 15 cm - 3 cm New Width = 12 cm

New Area Calculation

New Area = 19.2 cm * 12 cm New Area = 230.4 square cm

Percentage Change in Area

To calculate the percentage change in area, we can use the formula: Percentage Change = ((New Area - Initial Area) / Initial Area) * 100%.

Percentage Change = ((230.4 square cm - 360 square cm) / 360 square cm) * 100% Percentage Change = (-129.6 square cm / 360 square cm) * 100% Percentage Change ≈ -36%

The area of the rectangle will decrease by approximately 36% when each side is reduced by 20%.