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Finding the Fourth Proportional to 642.78, 962.13 and 489.30

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Solution

The fourth proportional to 642.78, 962.13 and 489.30 is: 732.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.78 : 962.13 = 489.30 : x
  2. Step 2: Convert to fraction form
    642.78/962.13 = 489.30/x
  3. Step 3: Cross multiply
    642.78x = 962.13 × 489.30
  4. Step 4: Simplify right side
    642.78x = 470,770.21
  5. Step 5: Solve for x
    x = 470,770.21/642.78
  6. Step 6: Final answer
    x = 732.40

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.