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Finding the Fourth Proportional to 81.25, 121.87 and 27.15

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Solution

The fourth proportional to 81.25, 121.87 and 27.15 is: 40.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.25 : 121.87 = 27.15 : x
  2. Step 2: Convert to fraction form
    81.25/121.87 = 27.15/x
  3. Step 3: Cross multiply
    81.25x = 121.87 × 27.15
  4. Step 4: Simplify right side
    81.25x = 3,308.77
  5. Step 5: Solve for x
    x = 3,308.77/81.25
  6. Step 6: Final answer
    x = 40.72

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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.