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Finding the Fourth Proportional to 1,139.38, 1,709.09 and 408.94

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Solution

The fourth proportional to 1,139.38, 1,709.09 and 408.94 is: 613.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.38 : 1,709.09 = 408.94 : x
  2. Step 2: Convert to fraction form
    1,139.38/1,709.09 = 408.94/x
  3. Step 3: Cross multiply
    1,139.38x = 1,709.09 × 408.94
  4. Step 4: Simplify right side
    1,139.38x = 698,915.26
  5. Step 5: Solve for x
    x = 698,915.26/1,139.38
  6. Step 6: Final answer
    x = 613.42

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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.