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Finding the Fourth Proportional to 686.41, 1,029.85 and 321

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Solution

The fourth proportional to 686.41, 1,029.85 and 321 is: 481.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.41 : 1,029.85 = 321 : x
  2. Step 2: Convert to fraction form
    686.41/1,029.85 = 321/x
  3. Step 3: Cross multiply
    686.41x = 1,029.85 × 321
  4. Step 4: Simplify right side
    686.41x = 330,581.85
  5. Step 5: Solve for x
    x = 330,581.85/686.41
  6. Step 6: Final answer
    x = 481.61

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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.