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Finding the Fourth Proportional to 413.68, 620.42 and 139.90

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Solution

The fourth proportional to 413.68, 620.42 and 139.90 is: 209.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    413.68 : 620.42 = 139.90 : x
  2. Step 2: Convert to fraction form
    413.68/620.42 = 139.90/x
  3. Step 3: Cross multiply
    413.68x = 620.42 × 139.90
  4. Step 4: Simplify right side
    413.68x = 86,796.76
  5. Step 5: Solve for x
    x = 86,796.76/413.68
  6. Step 6: Final answer
    x = 209.82

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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.