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Finding the Fourth Proportional to 394.30, 547.78 and 390.74

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Solution

The fourth proportional to 394.30, 547.78 and 390.74 is: 542.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    394.30 : 547.78 = 390.74 : x
  2. Step 2: Convert to fraction form
    394.30/547.78 = 390.74/x
  3. Step 3: Cross multiply
    394.30x = 547.78 × 390.74
  4. Step 4: Simplify right side
    394.30x = 214,039.56
  5. Step 5: Solve for x
    x = 214,039.56/394.30
  6. Step 6: Final answer
    x = 542.83

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.