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Finding the Fourth Proportional to 128.90, 176.31 and 126.98

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Solution

The fourth proportional to 128.90, 176.31 and 126.98 is: 173.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.90 : 176.31 = 126.98 : x
  2. Step 2: Convert to fraction form
    128.90/176.31 = 126.98/x
  3. Step 3: Cross multiply
    128.90x = 176.31 × 126.98
  4. Step 4: Simplify right side
    128.90x = 22,387.21
  5. Step 5: Solve for x
    x = 22,387.21/128.90
  6. Step 6: Final answer
    x = 173.68

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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.