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Finding the Fourth Proportional to 1,292.78, 1,939.14 and 380.78

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Solution

The fourth proportional to 1,292.78, 1,939.14 and 380.78 is: 571.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,292.78 : 1,939.14 = 380.78 : x
  2. Step 2: Convert to fraction form
    1,292.78/1,939.14 = 380.78/x
  3. Step 3: Cross multiply
    1,292.78x = 1,939.14 × 380.78
  4. Step 4: Simplify right side
    1,292.78x = 738,385.73
  5. Step 5: Solve for x
    x = 738,385.73/1,292.78
  6. Step 6: Final answer
    x = 571.16

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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.