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Finding the Fourth Proportional to 138.20, 207.30 and 84.20

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Solution

The fourth proportional to 138.20, 207.30 and 84.20 is: 126.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.20 : 207.30 = 84.20 : x
  2. Step 2: Convert to fraction form
    138.20/207.30 = 84.20/x
  3. Step 3: Cross multiply
    138.20x = 207.30 × 84.20
  4. Step 4: Simplify right side
    138.20x = 17,454.66
  5. Step 5: Solve for x
    x = 17,454.66/138.20
  6. Step 6: Final answer
    x = 126.30

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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.