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Finding the Fourth Proportional to 138.36, 207.54 and 80.40

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Solution

The fourth proportional to 138.36, 207.54 and 80.40 is: 120.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.36 : 207.54 = 80.40 : x
  2. Step 2: Convert to fraction form
    138.36/207.54 = 80.40/x
  3. Step 3: Cross multiply
    138.36x = 207.54 × 80.40
  4. Step 4: Simplify right side
    138.36x = 16,686.22
  5. Step 5: Solve for x
    x = 16,686.22/138.36
  6. Step 6: Final answer
    x = 120.60

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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.