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Finding the Fourth Proportional to 2,605, 3,908.14 and 781

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Solution

The fourth proportional to 2,605, 3,908.14 and 781 is: 1,171.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,605 : 3,908.14 = 781 : x
  2. Step 2: Convert to fraction form
    2,605/3,908.14 = 781/x
  3. Step 3: Cross multiply
    2,605x = 3,908.14 × 781
  4. Step 4: Simplify right side
    2,605x = 3,052,257.34
  5. Step 5: Solve for x
    x = 3,052,257.34/2,605
  6. Step 6: Final answer
    x = 1,171.69

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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.