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Finding the Fourth Proportional to 18.86, 28.30 and 9.85

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Solution

The fourth proportional to 18.86, 28.30 and 9.85 is: 14.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.86 : 28.30 = 9.85 : x
  2. Step 2: Convert to fraction form
    18.86/28.30 = 9.85/x
  3. Step 3: Cross multiply
    18.86x = 28.30 × 9.85
  4. Step 4: Simplify right side
    18.86x = 278.76
  5. Step 5: Solve for x
    x = 278.76/18.86
  6. Step 6: Final answer
    x = 14.78

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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.