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Finding the Fourth Proportional to 102.21, 140.82 and 85.55

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Solution

The fourth proportional to 102.21, 140.82 and 85.55 is: 117.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.21 : 140.82 = 85.55 : x
  2. Step 2: Convert to fraction form
    102.21/140.82 = 85.55/x
  3. Step 3: Cross multiply
    102.21x = 140.82 × 85.55
  4. Step 4: Simplify right side
    102.21x = 12,046.13
  5. Step 5: Solve for x
    x = 12,046.13/102.21
  6. Step 6: Final answer
    x = 117.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.