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Finding the Fourth Proportional to 128.78, 194.05 and 106.45

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Solution

The fourth proportional to 128.78, 194.05 and 106.45 is: 160.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.78 : 194.05 = 106.45 : x
  2. Step 2: Convert to fraction form
    128.78/194.05 = 106.45/x
  3. Step 3: Cross multiply
    128.78x = 194.05 × 106.45
  4. Step 4: Simplify right side
    128.78x = 20,656.62
  5. Step 5: Solve for x
    x = 20,656.62/128.78
  6. Step 6: Final answer
    x = 160.40

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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.