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Finding the Fourth Proportional to 413.89, 620.22 and 390.80

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Solution

The fourth proportional to 413.89, 620.22 and 390.80 is: 585.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    413.89 : 620.22 = 390.80 : x
  2. Step 2: Convert to fraction form
    413.89/620.22 = 390.80/x
  3. Step 3: Cross multiply
    413.89x = 620.22 × 390.80
  4. Step 4: Simplify right side
    413.89x = 242,381.98
  5. Step 5: Solve for x
    x = 242,381.98/413.89
  6. Step 6: Final answer
    x = 585.62

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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.