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Finding the Fourth Proportional to 138.83, 207.90 and 76.98

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Solution

The fourth proportional to 138.83, 207.90 and 76.98 is: 115.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.83 : 207.90 = 76.98 : x
  2. Step 2: Convert to fraction form
    138.83/207.90 = 76.98/x
  3. Step 3: Cross multiply
    138.83x = 207.90 × 76.98
  4. Step 4: Simplify right side
    138.83x = 16,004.14
  5. Step 5: Solve for x
    x = 16,004.14/138.83
  6. Step 6: Final answer
    x = 115.28

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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.