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Finding the Fourth Proportional to 278.71, 418.07 and 86.34

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Solution

The fourth proportional to 278.71, 418.07 and 86.34 is: 129.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.71 : 418.07 = 86.34 : x
  2. Step 2: Convert to fraction form
    278.71/418.07 = 86.34/x
  3. Step 3: Cross multiply
    278.71x = 418.07 × 86.34
  4. Step 4: Simplify right side
    278.71x = 36,096.16
  5. Step 5: Solve for x
    x = 36,096.16/278.71
  6. Step 6: Final answer
    x = 129.51

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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.