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Finding the Fourth Proportional to 81.53, 122.31 and 30.18

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Solution

The fourth proportional to 81.53, 122.31 and 30.18 is: 45.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.53 : 122.31 = 30.18 : x
  2. Step 2: Convert to fraction form
    81.53/122.31 = 30.18/x
  3. Step 3: Cross multiply
    81.53x = 122.31 × 30.18
  4. Step 4: Simplify right side
    81.53x = 3,691.32
  5. Step 5: Solve for x
    x = 3,691.32/81.53
  6. Step 6: Final answer
    x = 45.28

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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.