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Finding the Fourth Proportional to 138.12, 207.08 and 61.12

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Solution

The fourth proportional to 138.12, 207.08 and 61.12 is: 91.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.12 : 207.08 = 61.12 : x
  2. Step 2: Convert to fraction form
    138.12/207.08 = 61.12/x
  3. Step 3: Cross multiply
    138.12x = 207.08 × 61.12
  4. Step 4: Simplify right side
    138.12x = 12,656.73
  5. Step 5: Solve for x
    x = 12,656.73/138.12
  6. Step 6: Final answer
    x = 91.64

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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.