In the given triangle, ∠ACB = 90° and angle CAB = 60°, the value of cot ∠ABC is :

1. 2

2. 1

3. ${\sqrt3}$

4. $\dfrac{1}{\sqrt3}$

Let ∠ABC be x.

Using the angle sum property of a triangle, which states that the sum of all angles in a triangle is 180°:

⇒ ∠CAB + ∠ ACB + ∠ ABC = 180°

⇒ 60° + 90° + x = 180°

⇒ 150° + x = 180°

⇒ x = 180° - 150°

⇒ x = 30°

Now, cot ∠ABC = cot 30°

= $\sqrt3$

Hence, option 3 is the correct option.