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Finding the Fourth Proportional to 20.74, 31.09 and 8.71

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Solution

The fourth proportional to 20.74, 31.09 and 8.71 is: 13.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.74 : 31.09 = 8.71 : x
  2. Step 2: Convert to fraction form
    20.74/31.09 = 8.71/x
  3. Step 3: Cross multiply
    20.74x = 31.09 × 8.71
  4. Step 4: Simplify right side
    20.74x = 270.79
  5. Step 5: Solve for x
    x = 270.79/20.74
  6. Step 6: Final answer
    x = 13.06

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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.