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Finding the Fourth Proportional to 129.06, 193.62 and 85.81

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Solution

The fourth proportional to 129.06, 193.62 and 85.81 is: 128.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.06 : 193.62 = 85.81 : x
  2. Step 2: Convert to fraction form
    129.06/193.62 = 85.81/x
  3. Step 3: Cross multiply
    129.06x = 193.62 × 85.81
  4. Step 4: Simplify right side
    129.06x = 16,613.56
  5. Step 5: Solve for x
    x = 16,613.56/129.06
  6. Step 6: Final answer
    x = 128.73

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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.