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Finding the Fourth Proportional to 147.31, 221.06 and 85.55

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Solution

The fourth proportional to 147.31, 221.06 and 85.55 is: 128.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    147.31 : 221.06 = 85.55 : x
  2. Step 2: Convert to fraction form
    147.31/221.06 = 85.55/x
  3. Step 3: Cross multiply
    147.31x = 221.06 × 85.55
  4. Step 4: Simplify right side
    147.31x = 18,910.79
  5. Step 5: Solve for x
    x = 18,910.79/147.31
  6. Step 6: Final answer
    x = 128.38

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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.