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Finding the Fourth Proportional to 691.89, 1,038.38 and 281.31

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Solution

The fourth proportional to 691.89, 1,038.38 and 281.31 is: 422.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.89 : 1,038.38 = 281.31 : x
  2. Step 2: Convert to fraction form
    691.89/1,038.38 = 281.31/x
  3. Step 3: Cross multiply
    691.89x = 1,038.38 × 281.31
  4. Step 4: Simplify right side
    691.89x = 292,105.27
  5. Step 5: Solve for x
    x = 292,105.27/691.89
  6. Step 6: Final answer
    x = 422.18

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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.