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Finding the Fourth Proportional to 80.78, 121.02 and 40.12

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Solution

The fourth proportional to 80.78, 121.02 and 40.12 is: 60.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.78 : 121.02 = 40.12 : x
  2. Step 2: Convert to fraction form
    80.78/121.02 = 40.12/x
  3. Step 3: Cross multiply
    80.78x = 121.02 × 40.12
  4. Step 4: Simplify right side
    80.78x = 4,855.32
  5. Step 5: Solve for x
    x = 4,855.32/80.78
  6. Step 6: Final answer
    x = 60.11

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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.