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Finding the Fourth Proportional to 138.45, 207.66 and 77.39

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Solution

The fourth proportional to 138.45, 207.66 and 77.39 is: 116.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.45 : 207.66 = 77.39 : x
  2. Step 2: Convert to fraction form
    138.45/207.66 = 77.39/x
  3. Step 3: Cross multiply
    138.45x = 207.66 × 77.39
  4. Step 4: Simplify right side
    138.45x = 16,069.77
  5. Step 5: Solve for x
    x = 16,069.77/138.45
  6. Step 6: Final answer
    x = 116.07

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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.