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Finding the Fourth Proportional to 104.25, 156.18 and 81.31

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Solution

The fourth proportional to 104.25, 156.18 and 81.31 is: 121.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    104.25 : 156.18 = 81.31 : x
  2. Step 2: Convert to fraction form
    104.25/156.18 = 81.31/x
  3. Step 3: Cross multiply
    104.25x = 156.18 × 81.31
  4. Step 4: Simplify right side
    104.25x = 12,699.18
  5. Step 5: Solve for x
    x = 12,699.18/104.25
  6. Step 6: Final answer
    x = 121.82

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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.