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Finding the Fourth Proportional to 278.96, 418.30 and 86.54

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Solution

The fourth proportional to 278.96, 418.30 and 86.54 is: 129.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.96 : 418.30 = 86.54 : x
  2. Step 2: Convert to fraction form
    278.96/418.30 = 86.54/x
  3. Step 3: Cross multiply
    278.96x = 418.30 × 86.54
  4. Step 4: Simplify right side
    278.96x = 36,199.68
  5. Step 5: Solve for x
    x = 36,199.68/278.96
  6. Step 6: Final answer
    x = 129.77

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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.