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Finding the Fourth Proportional to 791.85, 1,187.78 and 380.89

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Solution

The fourth proportional to 791.85, 1,187.78 and 380.89 is: 571.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    791.85 : 1,187.78 = 380.89 : x
  2. Step 2: Convert to fraction form
    791.85/1,187.78 = 380.89/x
  3. Step 3: Cross multiply
    791.85x = 1,187.78 × 380.89
  4. Step 4: Simplify right side
    791.85x = 452,413.52
  5. Step 5: Solve for x
    x = 452,413.52/791.85
  6. Step 6: Final answer
    x = 571.34

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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.