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Finding the Fourth Proportional to 138.78, 191.52 and 109.62

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Solution

The fourth proportional to 138.78, 191.52 and 109.62 is: 151.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.78 : 191.52 = 109.62 : x
  2. Step 2: Convert to fraction form
    138.78/191.52 = 109.62/x
  3. Step 3: Cross multiply
    138.78x = 191.52 × 109.62
  4. Step 4: Simplify right side
    138.78x = 20,994.42
  5. Step 5: Solve for x
    x = 20,994.42/138.78
  6. Step 6: Final answer
    x = 151.28

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.