Explanation:

Here are the details and explanation for the problem:

- Two circles touch each other externally, meaning the distance between their centers equals the sum of their radii.

- The radius of the first circle (center A) is 18 cm.

- The radius of the second circle (center B) is 8 cm.

- The distance between the centers A and B = 18 cm + 8 cm = 26 cm.

- A property of tangents to circles touching each other externally is that the length of the common tangent is given by \(\sqrt{AB^2 - (r_1 - r_2)^2}\).

- Here, \(AB = 26\) cm and \(r_1 - r_2 = 18 - 8 = 10\) cm.

- Calculate the length of the tangent: \(\sqrt{26^2 - 10^2} = \sqrt{676 - 100} = \sqrt{576} = 24\) cm.

The correct option is:

- Option 3: 24 cm

Correct Answer: 24 cm