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Finding the Fourth Proportional to 128.12, 193.13 and 119.78

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Solution

The fourth proportional to 128.12, 193.13 and 119.78 is: 180.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.12 : 193.13 = 119.78 : x
  2. Step 2: Convert to fraction form
    128.12/193.13 = 119.78/x
  3. Step 3: Cross multiply
    128.12x = 193.13 × 119.78
  4. Step 4: Simplify right side
    128.12x = 23,131.55
  5. Step 5: Solve for x
    x = 23,131.55/128.12
  6. Step 6: Final answer
    x = 180.54

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.