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Finding the Fourth Proportional to 12.18, 16.82 and 7.81

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Solution

The fourth proportional to 12.18, 16.82 and 7.81 is: 10.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.18 : 16.82 = 7.81 : x
  2. Step 2: Convert to fraction form
    12.18/16.82 = 7.81/x
  3. Step 3: Cross multiply
    12.18x = 16.82 × 7.81
  4. Step 4: Simplify right side
    12.18x = 131.34
  5. Step 5: Solve for x
    x = 131.34/12.18
  6. Step 6: Final answer
    x = 10.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.