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Finding the Fourth Proportional to 129.57, 178.86 and 85.97

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Solution

The fourth proportional to 129.57, 178.86 and 85.97 is: 118.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.57 : 178.86 = 85.97 : x
  2. Step 2: Convert to fraction form
    129.57/178.86 = 85.97/x
  3. Step 3: Cross multiply
    129.57x = 178.86 × 85.97
  4. Step 4: Simplify right side
    129.57x = 15,375.70
  5. Step 5: Solve for x
    x = 15,375.70/129.57
  6. Step 6: Final answer
    x = 118.67

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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.