Solve for the missing factor in a percent equation: Find ? in 45 × ? = 25% of 900.

Introduction / Context:
This is a direct application of percentages and basic algebra. We equate a product to a percentage of a known number and solve for the unknown factor.

Given Data / Assumptions:

• Equation: 45 * ? = 25% of 900.
• 25% = 0.25.

Concept / Approach:
First evaluate the right-hand side (RHS). Then divide by 45 to find the unknown.

Step-by-Step Solution:

Verification / Alternative check:
Check: 45 * 5 = 225, which equals 25% of 900. The equation balances.

Why Other Options Are Wrong:

• 16.20 and 2.5 arise from arithmetic slips (e.g., dividing by 9 or 18 incorrectly).
• 4 gives 180 on the left, not 225.
• 500 is wildly off; it confuses percent with multiplication by 100.

Common Pitfalls:
Miscomputing 25% of 900; remember that 25% is one-fourth, and 900/4 = 225.

Final Answer:
5