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Finding the Fourth Proportional to 57.42, 86.15 and 47.84

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Solution

The fourth proportional to 57.42, 86.15 and 47.84 is: 71.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.42 : 86.15 = 47.84 : x
  2. Step 2: Convert to fraction form
    57.42/86.15 = 47.84/x
  3. Step 3: Cross multiply
    57.42x = 86.15 × 47.84
  4. Step 4: Simplify right side
    57.42x = 4,121.39
  5. Step 5: Solve for x
    x = 4,121.39/57.42
  6. Step 6: Final answer
    x = 71.78

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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.