Evaluate the expression.

Okay, let's evaluate the expression step by step.

First, we have the expression:

$$\frac{18}{4.5 \cdot 2.5}$$

Step 1: Multiply the numbers in the denominator.

$$4.5 \cdot 2.5 = 11.25$$

So, the expression becomes:

$$\frac{18}{11.25}$$

Step 2: Divide 18 by 11.25.

$$\frac{18}{11.25} = 1.6$$

So, the result is 1.6.

Answer: 1.6