The length of the rectangle is 12 m, and the width is 4 m. By what percentage will the area increase if its width is increased by 3 m.

1) Let’s find out what area a rectangle has if it is known that its length is 12 meters and its width is 4 meters.

12 * 4 = 48 m².

2) Let’s find out what width the rectangle has, if it is increased by 3 meters, if it is known that initially it had a width of 4 meters.

4 + 3 = 7 meters.

3) Find out what area a rectangle with sides of 12 m and 7 m has.

12 * 7 = 84 m².

4) Find out by what percentage the area has increased.

48 – 100%

84 – X%;

84 * 100/48 = 175%.

175 – 100 = 75%

Answer: the area of the rectangle has increased by 75%.