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Finding the Fourth Proportional to 34.31, 51.42 and 19.87

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Solution

The fourth proportional to 34.31, 51.42 and 19.87 is: 29.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    34.31 : 51.42 = 19.87 : x
  2. Step 2: Convert to fraction form
    34.31/51.42 = 19.87/x
  3. Step 3: Cross multiply
    34.31x = 51.42 × 19.87
  4. Step 4: Simplify right side
    34.31x = 1,021.72
  5. Step 5: Solve for x
    x = 1,021.72/34.31
  6. Step 6: Final answer
    x = 29.78

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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.