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Finding the Fourth Proportional to 761.40, 1,140.78 and 413.91

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Solution

The fourth proportional to 761.40, 1,140.78 and 413.91 is: 620.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    761.40 : 1,140.78 = 413.91 : x
  2. Step 2: Convert to fraction form
    761.40/1,140.78 = 413.91/x
  3. Step 3: Cross multiply
    761.40x = 1,140.78 × 413.91
  4. Step 4: Simplify right side
    761.40x = 472,181.80
  5. Step 5: Solve for x
    x = 472,181.80/761.40
  6. Step 6: Final answer
    x = 620.15

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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.