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Finding the Fourth Proportional to 31.49, 47.31 and 21.89

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Solution

The fourth proportional to 31.49, 47.31 and 21.89 is: 32.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.49 : 47.31 = 21.89 : x
  2. Step 2: Convert to fraction form
    31.49/47.31 = 21.89/x
  3. Step 3: Cross multiply
    31.49x = 47.31 × 21.89
  4. Step 4: Simplify right side
    31.49x = 1,035.38
  5. Step 5: Solve for x
    x = 1,035.38/31.49
  6. Step 6: Final answer
    x = 32.88

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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.