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Finding the Fourth Proportional to 138.78, 207.87 and 70.14

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Solution

The fourth proportional to 138.78, 207.87 and 70.14 is: 105.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.78 : 207.87 = 70.14 : x
  2. Step 2: Convert to fraction form
    138.78/207.87 = 70.14/x
  3. Step 3: Cross multiply
    138.78x = 207.87 × 70.14
  4. Step 4: Simplify right side
    138.78x = 14,580.00
  5. Step 5: Solve for x
    x = 14,580.00/138.78
  6. Step 6: Final answer
    x = 105.06

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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.