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Finding the Fourth Proportional to 131.78, 197.16 and 80.42

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Solution

The fourth proportional to 131.78, 197.16 and 80.42 is: 120.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    131.78 : 197.16 = 80.42 : x
  2. Step 2: Convert to fraction form
    131.78/197.16 = 80.42/x
  3. Step 3: Cross multiply
    131.78x = 197.16 × 80.42
  4. Step 4: Simplify right side
    131.78x = 15,855.61
  5. Step 5: Solve for x
    x = 15,855.61/131.78
  6. Step 6: Final answer
    x = 120.32

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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.