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Finding the Fourth Proportional to 128.46, 193.11 and 105.78

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Solution

The fourth proportional to 128.46, 193.11 and 105.78 is: 159.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.46 : 193.11 = 105.78 : x
  2. Step 2: Convert to fraction form
    128.46/193.11 = 105.78/x
  3. Step 3: Cross multiply
    128.46x = 193.11 × 105.78
  4. Step 4: Simplify right side
    128.46x = 20,427.18
  5. Step 5: Solve for x
    x = 20,427.18/128.46
  6. Step 6: Final answer
    x = 159.02

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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.