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Finding the Fourth Proportional to 81.53, 122.29 and 20.66

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Solution

The fourth proportional to 81.53, 122.29 and 20.66 is: 30.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.53 : 122.29 = 20.66 : x
  2. Step 2: Convert to fraction form
    81.53/122.29 = 20.66/x
  3. Step 3: Cross multiply
    81.53x = 122.29 × 20.66
  4. Step 4: Simplify right side
    81.53x = 2,526.51
  5. Step 5: Solve for x
    x = 2,526.51/81.53
  6. Step 6: Final answer
    x = 30.99

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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.