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Finding the Fourth Proportional to 31.38, 47.04 and 21.21

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Solution

The fourth proportional to 31.38, 47.04 and 21.21 is: 31.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.38 : 47.04 = 21.21 : x
  2. Step 2: Convert to fraction form
    31.38/47.04 = 21.21/x
  3. Step 3: Cross multiply
    31.38x = 47.04 × 21.21
  4. Step 4: Simplify right side
    31.38x = 997.72
  5. Step 5: Solve for x
    x = 997.72/31.38
  6. Step 6: Final answer
    x = 31.79

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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.