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Finding the Fourth Proportional to 679.83, 1,018.91 and 387.58

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Solution

The fourth proportional to 679.83, 1,018.91 and 387.58 is: 580.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.83 : 1,018.91 = 387.58 : x
  2. Step 2: Convert to fraction form
    679.83/1,018.91 = 387.58/x
  3. Step 3: Cross multiply
    679.83x = 1,018.91 × 387.58
  4. Step 4: Simplify right side
    679.83x = 394,909.14
  5. Step 5: Solve for x
    x = 394,909.14/679.83
  6. Step 6: Final answer
    x = 580.89

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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.