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Finding the Fourth Proportional to 15.15, 20.78 and 14.39

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Solution

The fourth proportional to 15.15, 20.78 and 14.39 is: 19.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.15 : 20.78 = 14.39 : x
  2. Step 2: Convert to fraction form
    15.15/20.78 = 14.39/x
  3. Step 3: Cross multiply
    15.15x = 20.78 × 14.39
  4. Step 4: Simplify right side
    15.15x = 298.85
  5. Step 5: Solve for x
    x = 298.85/15.15
  6. Step 6: Final answer
    x = 19.73

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.