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Finding the Fourth Proportional to 129.11, 178.16 and 76.69

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Solution

The fourth proportional to 129.11, 178.16 and 76.69 is: 105.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.11 : 178.16 = 76.69 : x
  2. Step 2: Convert to fraction form
    129.11/178.16 = 76.69/x
  3. Step 3: Cross multiply
    129.11x = 178.16 × 76.69
  4. Step 4: Simplify right side
    129.11x = 13,662.26
  5. Step 5: Solve for x
    x = 13,662.26/129.11
  6. Step 6: Final answer
    x = 105.82

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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.