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Finding the Fourth Proportional to 81.21, 122.25 and 74.03

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Solution

The fourth proportional to 81.21, 122.25 and 74.03 is: 111.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.21 : 122.25 = 74.03 : x
  2. Step 2: Convert to fraction form
    81.21/122.25 = 74.03/x
  3. Step 3: Cross multiply
    81.21x = 122.25 × 74.03
  4. Step 4: Simplify right side
    81.21x = 9,049.74
  5. Step 5: Solve for x
    x = 9,049.74/81.21
  6. Step 6: Final answer
    x = 111.44

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.