There is a rectangular steel plate with length of 200 cm, width of 100 cm and thickness of 3 cm. After forging, the width is unchanged and the length is increased by 20%. What is the thickness of the rectangular steel plate after forging? (solved by one-dimensional linear equation)

There is a rectangular steel plate with length of 200 cm, width of 100 cm and thickness of 3 cm. After forging, the width is unchanged and the length is increased by 20%. What is the thickness of the rectangular steel plate after forging? (solved by one-dimensional linear equation)

Let the thickness be x 200 * 100 * 3 = 200 * (1 + 20%) * 100 * x = > 1.2x = 3 = > x = 2.5 (CM)
Therefore, the thickness of the rectangular steel plate after forging is 2.5cm