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Finding the Fourth Proportional to 138.52, 208.14 and 128.56

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Solution

The fourth proportional to 138.52, 208.14 and 128.56 is: 193.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.52 : 208.14 = 128.56 : x
  2. Step 2: Convert to fraction form
    138.52/208.14 = 128.56/x
  3. Step 3: Cross multiply
    138.52x = 208.14 × 128.56
  4. Step 4: Simplify right side
    138.52x = 26,758.48
  5. Step 5: Solve for x
    x = 26,758.48/138.52
  6. Step 6: Final answer
    x = 193.17

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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.