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Finding the Fourth Proportional to 687.31, 1,029.34 and 558.79

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Solution

The fourth proportional to 687.31, 1,029.34 and 558.79 is: 836.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.31 : 1,029.34 = 558.79 : x
  2. Step 2: Convert to fraction form
    687.31/1,029.34 = 558.79/x
  3. Step 3: Cross multiply
    687.31x = 1,029.34 × 558.79
  4. Step 4: Simplify right side
    687.31x = 575,184.90
  5. Step 5: Solve for x
    x = 575,184.90/687.31
  6. Step 6: Final answer
    x = 836.86

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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.