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Finding the Fourth Proportional to 128.66, 176.38 and 125.21

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Solution

The fourth proportional to 128.66, 176.38 and 125.21 is: 171.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.66 : 176.38 = 125.21 : x
  2. Step 2: Convert to fraction form
    128.66/176.38 = 125.21/x
  3. Step 3: Cross multiply
    128.66x = 176.38 × 125.21
  4. Step 4: Simplify right side
    128.66x = 22,084.67
  5. Step 5: Solve for x
    x = 22,084.67/128.66
  6. Step 6: Final answer
    x = 171.66

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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.