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Finding the Fourth Proportional to 57.40, 86.10 and 43.90

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Solution

The fourth proportional to 57.40, 86.10 and 43.90 is: 65.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.40 : 86.10 = 43.90 : x
  2. Step 2: Convert to fraction form
    57.40/86.10 = 43.90/x
  3. Step 3: Cross multiply
    57.40x = 86.10 × 43.90
  4. Step 4: Simplify right side
    57.40x = 3,779.79
  5. Step 5: Solve for x
    x = 3,779.79/57.40
  6. Step 6: Final answer
    x = 65.85

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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.