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Finding the Fourth Proportional to 721.64, 1,081.62 and 413.64

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Solution

The fourth proportional to 721.64, 1,081.62 and 413.64 is: 619.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.64 : 1,081.62 = 413.64 : x
  2. Step 2: Convert to fraction form
    721.64/1,081.62 = 413.64/x
  3. Step 3: Cross multiply
    721.64x = 1,081.62 × 413.64
  4. Step 4: Simplify right side
    721.64x = 447,401.30
  5. Step 5: Solve for x
    x = 447,401.30/721.64
  6. Step 6: Final answer
    x = 619.98

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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.