The length of the rectangle is 12 cm and the width is 4 cm less. Find the perimeter and area of the rectangle.

The length of the rectangle is 12 cm and the width is 4 cm less. Find the perimeter and area of the rectangle. Find the area of a square with the same perimeter.

1) Determine the width of the rectangle: 12 – 4 = 8 (cm);
2) Calculate the perimeter of the rectangle using the formula: P = (a + b) 2 = (12 + 8) 2 = 40 (cm);
3) Find the area of a rectangle by the formula: S = a · b = 12 · 8 = 96 (cm²);
4) Knowing that the perimeters of the rectangle and the square are equal, we calculate the size of the side of the square: a = P: 4 = 40: 4 = 10 (cm);
5) Find the area of the square by the formula: S = a² = 10² = 100 (cm²).
Answer: the perimeter of the rectangle is 40 cm, the area of the rectangle is 96 cm², the area of the square is 100 cm².