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Finding the Fourth Proportional to 402.81, 558.48 and 389.31

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Solution

The fourth proportional to 402.81, 558.48 and 389.31 is: 539.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    402.81 : 558.48 = 389.31 : x
  2. Step 2: Convert to fraction form
    402.81/558.48 = 389.31/x
  3. Step 3: Cross multiply
    402.81x = 558.48 × 389.31
  4. Step 4: Simplify right side
    402.81x = 217,421.85
  5. Step 5: Solve for x
    x = 217,421.85/402.81
  6. Step 6: Final answer
    x = 539.76

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.