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Finding the Fourth Proportional to 413.68, 620.34 and 139.81

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Solution

The fourth proportional to 413.68, 620.34 and 139.81 is: 209.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    413.68 : 620.34 = 139.81 : x
  2. Step 2: Convert to fraction form
    413.68/620.34 = 139.81/x
  3. Step 3: Cross multiply
    413.68x = 620.34 × 139.81
  4. Step 4: Simplify right side
    413.68x = 86,729.74
  5. Step 5: Solve for x
    x = 86,729.74/413.68
  6. Step 6: Final answer
    x = 209.65

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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.