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Finding the Fourth Proportional to 1,387.96, 2,081.32 and 413.80

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Solution

The fourth proportional to 1,387.96, 2,081.32 and 413.80 is: 620.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.96 : 2,081.32 = 413.80 : x
  2. Step 2: Convert to fraction form
    1,387.96/2,081.32 = 413.80/x
  3. Step 3: Cross multiply
    1,387.96x = 2,081.32 × 413.80
  4. Step 4: Simplify right side
    1,387.96x = 861,250.22
  5. Step 5: Solve for x
    x = 861,250.22/1,387.96
  6. Step 6: Final answer
    x = 620.52

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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.