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Finding the Fourth Proportional to 154.05, 212.56 and 98.78

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Solution

The fourth proportional to 154.05, 212.56 and 98.78 is: 136.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    154.05 : 212.56 = 98.78 : x
  2. Step 2: Convert to fraction form
    154.05/212.56 = 98.78/x
  3. Step 3: Cross multiply
    154.05x = 212.56 × 98.78
  4. Step 4: Simplify right side
    154.05x = 20,997.28
  5. Step 5: Solve for x
    x = 20,997.28/154.05
  6. Step 6: Final answer
    x = 136.30

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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.