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Finding the Fourth Proportional to 81.17, 121.56 and 67.58

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Solution

The fourth proportional to 81.17, 121.56 and 67.58 is: 101.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.17 : 121.56 = 67.58 : x
  2. Step 2: Convert to fraction form
    81.17/121.56 = 67.58/x
  3. Step 3: Cross multiply
    81.17x = 121.56 × 67.58
  4. Step 4: Simplify right side
    81.17x = 8,215.02
  5. Step 5: Solve for x
    x = 8,215.02/81.17
  6. Step 6: Final answer
    x = 101.21

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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.