Explanation:

- Let's use the formulas for the sector of a circle.

- The area of the sector is given by the formula \((1/2) \times r \times \text{arc length}\).

- We know the area is 128 cm² and the arc length is 64 cm.

- Substitute these values into the formula: \(128 = (1/2) \times r \times 64\).

- Simplifying gives \(128 = 32r\).

- Solving for \(r\), we find \(r = 128 / 32 = 4\) cm.

- So, the radius of the circle is 4 cm.