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Finding the Fourth Proportional to 13.54, 20.35 and 7.85

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Solution

The fourth proportional to 13.54, 20.35 and 7.85 is: 11.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.54 : 20.35 = 7.85 : x
  2. Step 2: Convert to fraction form
    13.54/20.35 = 7.85/x
  3. Step 3: Cross multiply
    13.54x = 20.35 × 7.85
  4. Step 4: Simplify right side
    13.54x = 159.69
  5. Step 5: Solve for x
    x = 159.69/13.54
  6. Step 6: Final answer
    x = 11.79

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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.