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Finding the Fourth Proportional to 31.92, 47.86 and 21.08

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Solution

The fourth proportional to 31.92, 47.86 and 21.08 is: 31.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.92 : 47.86 = 21.08 : x
  2. Step 2: Convert to fraction form
    31.92/47.86 = 21.08/x
  3. Step 3: Cross multiply
    31.92x = 47.86 × 21.08
  4. Step 4: Simplify right side
    31.92x = 1,008.89
  5. Step 5: Solve for x
    x = 1,008.89/31.92
  6. Step 6: Final answer
    x = 31.61

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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.