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Finding the Fourth Proportional to 921.69, 1,379.32 and 868.39

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Solution

The fourth proportional to 921.69, 1,379.32 and 868.39 is: 1,299.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.69 : 1,379.32 = 868.39 : x
  2. Step 2: Convert to fraction form
    921.69/1,379.32 = 868.39/x
  3. Step 3: Cross multiply
    921.69x = 1,379.32 × 868.39
  4. Step 4: Simplify right side
    921.69x = 1,197,787.69
  5. Step 5: Solve for x
    x = 1,197,787.69/921.69
  6. Step 6: Final answer
    x = 1,299.56

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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.