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Finding the Fourth Proportional to 354.72, 489 and 311.04

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Solution

The fourth proportional to 354.72, 489 and 311.04 is: 428.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    354.72 : 489 = 311.04 : x
  2. Step 2: Convert to fraction form
    354.72/489 = 311.04/x
  3. Step 3: Cross multiply
    354.72x = 489 × 311.04
  4. Step 4: Simplify right side
    354.72x = 152,098.56
  5. Step 5: Solve for x
    x = 152,098.56/354.72
  6. Step 6: Final answer
    x = 428.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.