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Finding the Fourth Proportional to 390.61, 539.31 and 259.89

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Solution

The fourth proportional to 390.61, 539.31 and 259.89 is: 358.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.61 : 539.31 = 259.89 : x
  2. Step 2: Convert to fraction form
    390.61/539.31 = 259.89/x
  3. Step 3: Cross multiply
    390.61x = 539.31 × 259.89
  4. Step 4: Simplify right side
    390.61x = 140,161.28
  5. Step 5: Solve for x
    x = 140,161.28/390.61
  6. Step 6: Final answer
    x = 358.83

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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.