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Finding the Fourth Proportional to 30.31, 41.80 and 20.61

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Solution

The fourth proportional to 30.31, 41.80 and 20.61 is: 28.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.31 : 41.80 = 20.61 : x
  2. Step 2: Convert to fraction form
    30.31/41.80 = 20.61/x
  3. Step 3: Cross multiply
    30.31x = 41.80 × 20.61
  4. Step 4: Simplify right side
    30.31x = 861.50
  5. Step 5: Solve for x
    x = 861.50/30.31
  6. Step 6: Final answer
    x = 28.42

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.