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Finding the Fourth Proportional to 25.31, 38.17 and 20.86

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Solution

The fourth proportional to 25.31, 38.17 and 20.86 is: 31.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    25.31 : 38.17 = 20.86 : x
  2. Step 2: Convert to fraction form
    25.31/38.17 = 20.86/x
  3. Step 3: Cross multiply
    25.31x = 38.17 × 20.86
  4. Step 4: Simplify right side
    25.31x = 796.16
  5. Step 5: Solve for x
    x = 796.16/25.31
  6. Step 6: Final answer
    x = 31.45

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.