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Finding the Fourth Proportional to 12.18, 18.21 and 9.18

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Solution

The fourth proportional to 12.18, 18.21 and 9.18 is: 13.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.18 : 18.21 = 9.18 : x
  2. Step 2: Convert to fraction form
    12.18/18.21 = 9.18/x
  3. Step 3: Cross multiply
    12.18x = 18.21 × 9.18
  4. Step 4: Simplify right side
    12.18x = 167.17
  5. Step 5: Solve for x
    x = 167.17/12.18
  6. Step 6: Final answer
    x = 13.72

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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.