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Finding the Fourth Proportional to 15.15, 20.90 and 9.97

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Solution

The fourth proportional to 15.15, 20.90 and 9.97 is: 13.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.15 : 20.90 = 9.97 : x
  2. Step 2: Convert to fraction form
    15.15/20.90 = 9.97/x
  3. Step 3: Cross multiply
    15.15x = 20.90 × 9.97
  4. Step 4: Simplify right side
    15.15x = 208.38
  5. Step 5: Solve for x
    x = 208.38/15.15
  6. Step 6: Final answer
    x = 13.76

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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.