Final answer:
To solve the proportion z / 3.5 = 18 / 36, cross-multiply and solve for z. The solution is z = 1.75.
Step-by-step explanation:
To solve the proportion z / 3.5 = 18 / 36, we can cross-multiply. This means multiplying the numerator on one side by the denominator on the other side. So, we get 36z = 3.5 * 18. Next, divide both sides of the equation by 36 to isolate z. Thus, the solution is z = 3.5 * 18 / 36, which simplifies to z = 1.75.