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Finding the Fourth Proportional to 42.05, 63.11 and 31.86

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Solution

The fourth proportional to 42.05, 63.11 and 31.86 is: 47.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.05 : 63.11 = 31.86 : x
  2. Step 2: Convert to fraction form
    42.05/63.11 = 31.86/x
  3. Step 3: Cross multiply
    42.05x = 63.11 × 31.86
  4. Step 4: Simplify right side
    42.05x = 2,010.76
  5. Step 5: Solve for x
    x = 2,010.76/42.05
  6. Step 6: Final answer
    x = 47.82

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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.