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Finding the Fourth Proportional to 128.60, 178.28 and 126.09

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Solution

The fourth proportional to 128.60, 178.28 and 126.09 is: 174.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.60 : 178.28 = 126.09 : x
  2. Step 2: Convert to fraction form
    128.60/178.28 = 126.09/x
  3. Step 3: Cross multiply
    128.60x = 178.28 × 126.09
  4. Step 4: Simplify right side
    128.60x = 22,479.17
  5. Step 5: Solve for x
    x = 22,479.17/128.60
  6. Step 6: Final answer
    x = 174.80

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.