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Finding the Fourth Proportional to 129.76, 178.74 and 123.28

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Solution

The fourth proportional to 129.76, 178.74 and 123.28 is: 169.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.76 : 178.74 = 123.28 : x
  2. Step 2: Convert to fraction form
    129.76/178.74 = 123.28/x
  3. Step 3: Cross multiply
    129.76x = 178.74 × 123.28
  4. Step 4: Simplify right side
    129.76x = 22,034.62
  5. Step 5: Solve for x
    x = 22,034.62/129.76
  6. Step 6: Final answer
    x = 169.81

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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.