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Finding the Fourth Proportional to 154.81, 213.45 and 128.61

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Solution

The fourth proportional to 154.81, 213.45 and 128.61 is: 177.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    154.81 : 213.45 = 128.61 : x
  2. Step 2: Convert to fraction form
    154.81/213.45 = 128.61/x
  3. Step 3: Cross multiply
    154.81x = 213.45 × 128.61
  4. Step 4: Simplify right side
    154.81x = 27,451.80
  5. Step 5: Solve for x
    x = 27,451.80/154.81
  6. Step 6: Final answer
    x = 177.33

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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.