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Finding the Fourth Proportional to 138.48, 207.12 and 120.72

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Solution

The fourth proportional to 138.48, 207.12 and 120.72 is: 180.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.48 : 207.12 = 120.72 : x
  2. Step 2: Convert to fraction form
    138.48/207.12 = 120.72/x
  3. Step 3: Cross multiply
    138.48x = 207.12 × 120.72
  4. Step 4: Simplify right side
    138.48x = 25,003.53
  5. Step 5: Solve for x
    x = 25,003.53/138.48
  6. Step 6: Final answer
    x = 180.56

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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.