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Finding the Fourth Proportional to 11.15, 15.42 and 9.79

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Solution

The fourth proportional to 11.15, 15.42 and 9.79 is: 13.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    11.15 : 15.42 = 9.79 : x
  2. Step 2: Convert to fraction form
    11.15/15.42 = 9.79/x
  3. Step 3: Cross multiply
    11.15x = 15.42 × 9.79
  4. Step 4: Simplify right side
    11.15x = 150.96
  5. Step 5: Solve for x
    x = 150.96/11.15
  6. Step 6: Final answer
    x = 13.54

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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.