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Finding the Fourth Proportional to 693.78, 1,039.86 and 308.76

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Solution

The fourth proportional to 693.78, 1,039.86 and 308.76 is: 462.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    693.78 : 1,039.86 = 308.76 : x
  2. Step 2: Convert to fraction form
    693.78/1,039.86 = 308.76/x
  3. Step 3: Cross multiply
    693.78x = 1,039.86 × 308.76
  4. Step 4: Simplify right side
    693.78x = 321,067.17
  5. Step 5: Solve for x
    x = 321,067.17/693.78
  6. Step 6: Final answer
    x = 462.78

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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.