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Finding the Fourth Proportional to 138.83, 207.23 and 128.81

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Solution

The fourth proportional to 138.83, 207.23 and 128.81 is: 192.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.83 : 207.23 = 128.81 : x
  2. Step 2: Convert to fraction form
    138.83/207.23 = 128.81/x
  3. Step 3: Cross multiply
    138.83x = 207.23 × 128.81
  4. Step 4: Simplify right side
    138.83x = 26,693.17
  5. Step 5: Solve for x
    x = 26,693.17/138.83
  6. Step 6: Final answer
    x = 192.28

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.