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Finding the Fourth Proportional to 25.31, 38 and 21.09

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Solution

The fourth proportional to 25.31, 38 and 21.09 is: 31.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    25.31 : 38 = 21.09 : x
  2. Step 2: Convert to fraction form
    25.31/38 = 21.09/x
  3. Step 3: Cross multiply
    25.31x = 38 × 21.09
  4. Step 4: Simplify right side
    25.31x = 801.42
  5. Step 5: Solve for x
    x = 801.42/25.31
  6. Step 6: Final answer
    x = 31.66

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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.