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Finding the Fourth Proportional to 129.20, 193.80 and 111.20

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Solution

The fourth proportional to 129.20, 193.80 and 111.20 is: 166.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.20 : 193.80 = 111.20 : x
  2. Step 2: Convert to fraction form
    129.20/193.80 = 111.20/x
  3. Step 3: Cross multiply
    129.20x = 193.80 × 111.20
  4. Step 4: Simplify right side
    129.20x = 21,550.56
  5. Step 5: Solve for x
    x = 21,550.56/129.20
  6. Step 6: Final answer
    x = 166.80

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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.