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Finding the Fourth Proportional to 11.20, 15.45 and 7.11

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Solution

The fourth proportional to 11.20, 15.45 and 7.11 is: 9.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    11.20 : 15.45 = 7.11 : x
  2. Step 2: Convert to fraction form
    11.20/15.45 = 7.11/x
  3. Step 3: Cross multiply
    11.20x = 15.45 × 7.11
  4. Step 4: Simplify right side
    11.20x = 109.77
  5. Step 5: Solve for x
    x = 109.77/11.20
  6. Step 6: Final answer
    x = 9.81

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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.