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Finding the Fourth Proportional to 74.12, 111.21 and 39.86

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Solution

The fourth proportional to 74.12, 111.21 and 39.86 is: 59.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.12 : 111.21 = 39.86 : x
  2. Step 2: Convert to fraction form
    74.12/111.21 = 39.86/x
  3. Step 3: Cross multiply
    74.12x = 111.21 × 39.86
  4. Step 4: Simplify right side
    74.12x = 4,432.83
  5. Step 5: Solve for x
    x = 4,432.83/74.12
  6. Step 6: Final answer
    x = 59.81

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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.