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Finding the Fourth Proportional to 129.11, 193.87 and 80.45

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Solution

The fourth proportional to 129.11, 193.87 and 80.45 is: 120.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.11 : 193.87 = 80.45 : x
  2. Step 2: Convert to fraction form
    129.11/193.87 = 80.45/x
  3. Step 3: Cross multiply
    129.11x = 193.87 × 80.45
  4. Step 4: Simplify right side
    129.11x = 15,596.84
  5. Step 5: Solve for x
    x = 15,596.84/129.11
  6. Step 6: Final answer
    x = 120.80

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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.