Final answer:
The length of the unknown side in the smaller triangle is 8 cm.
Step-by-step explanation:
In the given problem, we have two similar triangles. The problem states that the dimensions of the larger triangle are twice the dimensions of the smaller triangle. Let's say the length of the unknown side in the smaller triangle is x cm. According to the scale factor, the length of the corresponding side in the larger triangle would be 2x cm. To find the value of x, we need to compare the given options with the length of the corresponding side in the larger triangle. The correct option would be the one where x equals the length of the corresponding side in the larger triangle. In this case, the correct answer is x = 8 cm, option B.