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Finding the Fourth Proportional to 129.87, 194.90 and 86.45

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Solution

The fourth proportional to 129.87, 194.90 and 86.45 is: 129.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.87 : 194.90 = 86.45 : x
  2. Step 2: Convert to fraction form
    129.87/194.90 = 86.45/x
  3. Step 3: Cross multiply
    129.87x = 194.90 × 86.45
  4. Step 4: Simplify right side
    129.87x = 16,847.70
  5. Step 5: Solve for x
    x = 16,847.70/129.87
  6. Step 6: Final answer
    x = 129.73

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.