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Finding the Fourth Proportional to 138.60, 207.81 and 70.11

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Solution

The fourth proportional to 138.60, 207.81 and 70.11 is: 105.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.60 : 207.81 = 70.11 : x
  2. Step 2: Convert to fraction form
    138.60/207.81 = 70.11/x
  3. Step 3: Cross multiply
    138.60x = 207.81 × 70.11
  4. Step 4: Simplify right side
    138.60x = 14,569.56
  5. Step 5: Solve for x
    x = 14,569.56/138.60
  6. Step 6: Final answer
    x = 105.12

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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.