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Finding the Fourth Proportional to 128.83, 177.28 and 103.72

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Solution

The fourth proportional to 128.83, 177.28 and 103.72 is: 142.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.83 : 177.28 = 103.72 : x
  2. Step 2: Convert to fraction form
    128.83/177.28 = 103.72/x
  3. Step 3: Cross multiply
    128.83x = 177.28 × 103.72
  4. Step 4: Simplify right side
    128.83x = 18,387.48
  5. Step 5: Solve for x
    x = 18,387.48/128.83
  6. Step 6: Final answer
    x = 142.73

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.