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Finding the Fourth Proportional to 687, 1,029.77 and 321.48

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Solution

The fourth proportional to 687, 1,029.77 and 321.48 is: 481.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    687 : 1,029.77 = 321.48 : x
  2. Step 2: Convert to fraction form
    687/1,029.77 = 321.48/x
  3. Step 3: Cross multiply
    687x = 1,029.77 × 321.48
  4. Step 4: Simplify right side
    687x = 331,048.85
  5. Step 5: Solve for x
    x = 331,048.85/687
  6. Step 6: Final answer
    x = 481.88

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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.