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Finding the Fourth Proportional to 279.31, 418.92 and 81.64

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Solution

The fourth proportional to 279.31, 418.92 and 81.64 is: 122.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.31 : 418.92 = 81.64 : x
  2. Step 2: Convert to fraction form
    279.31/418.92 = 81.64/x
  3. Step 3: Cross multiply
    279.31x = 418.92 × 81.64
  4. Step 4: Simplify right side
    279.31x = 34,201.31
  5. Step 5: Solve for x
    x = 34,201.31/279.31
  6. Step 6: Final answer
    x = 122.45

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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.