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Finding the Fourth Proportional to 1,386, 2,078.60 and 411.87

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Solution

The fourth proportional to 1,386, 2,078.60 and 411.87 is: 617.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,386 : 2,078.60 = 411.87 : x
  2. Step 2: Convert to fraction form
    1,386/2,078.60 = 411.87/x
  3. Step 3: Cross multiply
    1,386x = 2,078.60 × 411.87
  4. Step 4: Simplify right side
    1,386x = 856,110.92
  5. Step 5: Solve for x
    x = 856,110.92/1,386
  6. Step 6: Final answer
    x = 617.68

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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.