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Finding the Fourth Proportional to 80.90, 121.18 and 63.78

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Solution

The fourth proportional to 80.90, 121.18 and 63.78 is: 95.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.90 : 121.18 = 63.78 : x
  2. Step 2: Convert to fraction form
    80.90/121.18 = 63.78/x
  3. Step 3: Cross multiply
    80.90x = 121.18 × 63.78
  4. Step 4: Simplify right side
    80.90x = 7,728.86
  5. Step 5: Solve for x
    x = 7,728.86/80.90
  6. Step 6: Final answer
    x = 95.54

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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.