Final answer:
The side length of a square that has the same area as a rectangle with dimensions 20cm by 5cm is 10 centimeters.
Step-by-step explanation:
The student is asked to calculate the length of the side of a square that has the same area as a given rectangle. The rectangle has a length of 20cm and a width of 5cm. To find the area of the rectangle, we multiply the length by the width:
Area of the rectangle = Length × Width = 20cm × 5cm = 100cm²
Since we want to find a square with the same area, and the area of a square is the side length squared (s²), we need to find the square root of the rectangle's area to find the length of the square's side:
Length of the square's side = √(Area of the square) = √100cm² = 10cm
Therefore, the side of the square that is equivalent in area to the rectangle is 10 centimeters long.