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Finding the Fourth Proportional to 129.12, 178.22 and 77.38

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Solution

The fourth proportional to 129.12, 178.22 and 77.38 is: 106.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.12 : 178.22 = 77.38 : x
  2. Step 2: Convert to fraction form
    129.12/178.22 = 77.38/x
  3. Step 3: Cross multiply
    129.12x = 178.22 × 77.38
  4. Step 4: Simplify right side
    129.12x = 13,790.66
  5. Step 5: Solve for x
    x = 13,790.66/129.12
  6. Step 6: Final answer
    x = 106.81

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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.