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Finding the Fourth Proportional to 102.78, 154.02 and 79.98

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Solution

The fourth proportional to 102.78, 154.02 and 79.98 is: 119.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.78 : 154.02 = 79.98 : x
  2. Step 2: Convert to fraction form
    102.78/154.02 = 79.98/x
  3. Step 3: Cross multiply
    102.78x = 154.02 × 79.98
  4. Step 4: Simplify right side
    102.78x = 12,318.52
  5. Step 5: Solve for x
    x = 12,318.52/102.78
  6. Step 6: Final answer
    x = 119.85

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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.