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Finding the Fourth Proportional to 390.86, 537.94 and 311.92

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Solution

The fourth proportional to 390.86, 537.94 and 311.92 is: 429.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.86 : 537.94 = 311.92 : x
  2. Step 2: Convert to fraction form
    390.86/537.94 = 311.92/x
  3. Step 3: Cross multiply
    390.86x = 537.94 × 311.92
  4. Step 4: Simplify right side
    390.86x = 167,793.29
  5. Step 5: Solve for x
    x = 167,793.29/390.86
  6. Step 6: Final answer
    x = 429.29

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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.