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Finding the Fourth Proportional to 80.75, 120.87 and 42.18

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Solution

The fourth proportional to 80.75, 120.87 and 42.18 is: 63.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.75 : 120.87 = 42.18 : x
  2. Step 2: Convert to fraction form
    80.75/120.87 = 42.18/x
  3. Step 3: Cross multiply
    80.75x = 120.87 × 42.18
  4. Step 4: Simplify right side
    80.75x = 5,098.30
  5. Step 5: Solve for x
    x = 5,098.30/80.75
  6. Step 6: Final answer
    x = 63.14

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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.