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Finding the Fourth Proportional to 81.42, 122.14 and 30.05

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Solution

The fourth proportional to 81.42, 122.14 and 30.05 is: 45.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.42 : 122.14 = 30.05 : x
  2. Step 2: Convert to fraction form
    81.42/122.14 = 30.05/x
  3. Step 3: Cross multiply
    81.42x = 122.14 × 30.05
  4. Step 4: Simplify right side
    81.42x = 3,669.62
  5. Step 5: Solve for x
    x = 3,669.62/81.42
  6. Step 6: Final answer
    x = 45.07

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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.