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Finding the Fourth Proportional to 80.50, 120.36 and 78.68

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Solution

The fourth proportional to 80.50, 120.36 and 78.68 is: 117.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.50 : 120.36 = 78.68 : x
  2. Step 2: Convert to fraction form
    80.50/120.36 = 78.68/x
  3. Step 3: Cross multiply
    80.50x = 120.36 × 78.68
  4. Step 4: Simplify right side
    80.50x = 9,469.92
  5. Step 5: Solve for x
    x = 9,469.92/80.50
  6. Step 6: Final answer
    x = 117.64

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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.