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Finding the Fourth Proportional to 619.90, 929.85 and 413.80

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Solution

The fourth proportional to 619.90, 929.85 and 413.80 is: 620.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    619.90 : 929.85 = 413.80 : x
  2. Step 2: Convert to fraction form
    619.90/929.85 = 413.80/x
  3. Step 3: Cross multiply
    619.90x = 929.85 × 413.80
  4. Step 4: Simplify right side
    619.90x = 384,771.93
  5. Step 5: Solve for x
    x = 384,771.93/619.90
  6. Step 6: Final answer
    x = 620.70

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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.