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Finding the Fourth Proportional to 133.42, 199.87 and 81.91

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Solution

The fourth proportional to 133.42, 199.87 and 81.91 is: 122.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    133.42 : 199.87 = 81.91 : x
  2. Step 2: Convert to fraction form
    133.42/199.87 = 81.91/x
  3. Step 3: Cross multiply
    133.42x = 199.87 × 81.91
  4. Step 4: Simplify right side
    133.42x = 16,370.65
  5. Step 5: Solve for x
    x = 16,370.65/133.42
  6. Step 6: Final answer
    x = 122.70

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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.