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Finding the Fourth Proportional to 31.72, 47.58 and 21.61

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Solution

The fourth proportional to 31.72, 47.58 and 21.61 is: 32.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.72 : 47.58 = 21.61 : x
  2. Step 2: Convert to fraction form
    31.72/47.58 = 21.61/x
  3. Step 3: Cross multiply
    31.72x = 47.58 × 21.61
  4. Step 4: Simplify right side
    31.72x = 1,028.20
  5. Step 5: Solve for x
    x = 1,028.20/31.72
  6. Step 6: Final answer
    x = 32.42

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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.