Answer: 5 cm^2
Explanation:
When a shape is enlarged by a scale factor of 1/2, its area is multiplied by the square of the scale factor, which is (1/2)^2 = 1/4.
So, if the original shape S has an area of 20 cm^2, then the area of the enlarged shape is:
Area of enlarged shape = Area of original shape x (scale factor)^2
Area of enlarged shape = 20 cm^2 x (1/4)
Area of enlarged shape = 5 cm^2
Therefore, the area of the enlarged shape is 5 cm^2.