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Finding the Fourth Proportional to 57.80, 86.70 and 38.60

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Solution

The fourth proportional to 57.80, 86.70 and 38.60 is: 57.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.80 : 86.70 = 38.60 : x
  2. Step 2: Convert to fraction form
    57.80/86.70 = 38.60/x
  3. Step 3: Cross multiply
    57.80x = 86.70 × 38.60
  4. Step 4: Simplify right side
    57.80x = 3,346.62
  5. Step 5: Solve for x
    x = 3,346.62/57.80
  6. Step 6: Final answer
    x = 57.90

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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.