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Finding the Fourth Proportional to 12.31, 18.48 and 8.91

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Solution

The fourth proportional to 12.31, 18.48 and 8.91 is: 13.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.31 : 18.48 = 8.91 : x
  2. Step 2: Convert to fraction form
    12.31/18.48 = 8.91/x
  3. Step 3: Cross multiply
    12.31x = 18.48 × 8.91
  4. Step 4: Simplify right side
    12.31x = 164.76
  5. Step 5: Solve for x
    x = 164.76/12.31
  6. Step 6: Final answer
    x = 13.39

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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.