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Finding the Fourth Proportional to 128.78, 176.54 and 126.88

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Solution

The fourth proportional to 128.78, 176.54 and 126.88 is: 173.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.78 : 176.54 = 126.88 : x
  2. Step 2: Convert to fraction form
    128.78/176.54 = 126.88/x
  3. Step 3: Cross multiply
    128.78x = 176.54 × 126.88
  4. Step 4: Simplify right side
    128.78x = 22,399.40
  5. Step 5: Solve for x
    x = 22,399.40/128.78
  6. Step 6: Final answer
    x = 173.94

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.