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Finding the Fourth Proportional to 685.38, 1,028.10 and 413.22

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Solution

The fourth proportional to 685.38, 1,028.10 and 413.22 is: 619.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.38 : 1,028.10 = 413.22 : x
  2. Step 2: Convert to fraction form
    685.38/1,028.10 = 413.22/x
  3. Step 3: Cross multiply
    685.38x = 1,028.10 × 413.22
  4. Step 4: Simplify right side
    685.38x = 424,831.48
  5. Step 5: Solve for x
    x = 424,831.48/685.38
  6. Step 6: Final answer
    x = 619.85

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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.