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Finding the Fourth Proportional to 721.49, 1,081.62 and 413.80

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Solution

The fourth proportional to 721.49, 1,081.62 and 413.80 is: 620.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.49 : 1,081.62 = 413.80 : x
  2. Step 2: Convert to fraction form
    721.49/1,081.62 = 413.80/x
  3. Step 3: Cross multiply
    721.49x = 1,081.62 × 413.80
  4. Step 4: Simplify right side
    721.49x = 447,574.36
  5. Step 5: Solve for x
    x = 447,574.36/721.49
  6. Step 6: Final answer
    x = 620.35

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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.