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Finding the Fourth Proportional to 686.79, 1,029.71 and 321.38

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Solution

The fourth proportional to 686.79, 1,029.71 and 321.38 is: 481.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.79 : 1,029.71 = 321.38 : x
  2. Step 2: Convert to fraction form
    686.79/1,029.71 = 321.38/x
  3. Step 3: Cross multiply
    686.79x = 1,029.71 × 321.38
  4. Step 4: Simplify right side
    686.79x = 330,921.44
  5. Step 5: Solve for x
    x = 330,921.44/686.79
  6. Step 6: Final answer
    x = 481.84

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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.