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Finding the Fourth Proportional to 42.60, 63.84 and 31.89

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Solution

The fourth proportional to 42.60, 63.84 and 31.89 is: 47.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.60 : 63.84 = 31.89 : x
  2. Step 2: Convert to fraction form
    42.60/63.84 = 31.89/x
  3. Step 3: Cross multiply
    42.60x = 63.84 × 31.89
  4. Step 4: Simplify right side
    42.60x = 2,035.86
  5. Step 5: Solve for x
    x = 2,035.86/42.60
  6. Step 6: Final answer
    x = 47.79

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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.