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Finding the Fourth Proportional to 140.91, 211.31 and 85.84

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Solution

The fourth proportional to 140.91, 211.31 and 85.84 is: 128.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.91 : 211.31 = 85.84 : x
  2. Step 2: Convert to fraction form
    140.91/211.31 = 85.84/x
  3. Step 3: Cross multiply
    140.91x = 211.31 × 85.84
  4. Step 4: Simplify right side
    140.91x = 18,139.40
  5. Step 5: Solve for x
    x = 18,139.40/140.91
  6. Step 6: Final answer
    x = 128.73

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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.