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Finding the Fourth Proportional to 12.15, 18.19 and 9.90

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Solution

The fourth proportional to 12.15, 18.19 and 9.90 is: 14.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.15 : 18.19 = 9.90 : x
  2. Step 2: Convert to fraction form
    12.15/18.19 = 9.90/x
  3. Step 3: Cross multiply
    12.15x = 18.19 × 9.90
  4. Step 4: Simplify right side
    12.15x = 180.08
  5. Step 5: Solve for x
    x = 180.08/12.15
  6. Step 6: Final answer
    x = 14.82

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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.