Final answer:
The value of x in the rectangle with dimensions (2 1/2 + x) cm and 2 1/2 cm is 0 cm (option A).
Step-by-step explanation:
To find the value of x in the rectangle with dimensions (2 1/2 + x) cm and 2 1/2 cm, we need to set up an equation. The width of the rectangle is given by (2 1/2 + x) cm, and we know that it is between 1.2 and 1.3 cm. From the information given, we can determine that the width of the rectangle is 1.25 cm.
So, (2 1/2 + x) cm = 1.25 cm. To solve for x, we can subtract 2 1/2 from both sides of the equation:
x cm = 1.25 cm - 2 1/2 cm = -1.25 cm.
Since we're measuring a length, the negative value doesn't make sense. Therefore, the value of x is 0 cm (option A).