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Finding the Fourth Proportional to 278.94, 418.42 and 86.52

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Solution

The fourth proportional to 278.94, 418.42 and 86.52 is: 129.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.94 : 418.42 = 86.52 : x
  2. Step 2: Convert to fraction form
    278.94/418.42 = 86.52/x
  3. Step 3: Cross multiply
    278.94x = 418.42 × 86.52
  4. Step 4: Simplify right side
    278.94x = 36,201.70
  5. Step 5: Solve for x
    x = 36,201.70/278.94
  6. Step 6: Final answer
    x = 129.78

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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.