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Finding the Fourth Proportional to 138.28, 209.20 and 137.20

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Solution

The fourth proportional to 138.28, 209.20 and 137.20 is: 207.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.28 : 209.20 = 137.20 : x
  2. Step 2: Convert to fraction form
    138.28/209.20 = 137.20/x
  3. Step 3: Cross multiply
    138.28x = 209.20 × 137.20
  4. Step 4: Simplify right side
    138.28x = 28,702.24
  5. Step 5: Solve for x
    x = 28,702.24/138.28
  6. Step 6: Final answer
    x = 207.57

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.