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Finding the Fourth Proportional to 81.47, 121.98 and 69.32

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Solution

The fourth proportional to 81.47, 121.98 and 69.32 is: 103.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.47 : 121.98 = 69.32 : x
  2. Step 2: Convert to fraction form
    81.47/121.98 = 69.32/x
  3. Step 3: Cross multiply
    81.47x = 121.98 × 69.32
  4. Step 4: Simplify right side
    81.47x = 8,455.65
  5. Step 5: Solve for x
    x = 8,455.65/81.47
  6. Step 6: Final answer
    x = 103.79

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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.