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Finding the Fourth Proportional to 929.81, 1,394.78 and 280.55

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Solution

The fourth proportional to 929.81, 1,394.78 and 280.55 is: 420.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    929.81 : 1,394.78 = 280.55 : x
  2. Step 2: Convert to fraction form
    929.81/1,394.78 = 280.55/x
  3. Step 3: Cross multiply
    929.81x = 1,394.78 × 280.55
  4. Step 4: Simplify right side
    929.81x = 391,307.61
  5. Step 5: Solve for x
    x = 391,307.61/929.81
  6. Step 6: Final answer
    x = 420.85

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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.