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Finding the Fourth Proportional to 13.76, 20.64 and 7.76

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Solution

The fourth proportional to 13.76, 20.64 and 7.76 is: 11.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.76 : 20.64 = 7.76 : x
  2. Step 2: Convert to fraction form
    13.76/20.64 = 7.76/x
  3. Step 3: Cross multiply
    13.76x = 20.64 × 7.76
  4. Step 4: Simplify right side
    13.76x = 160.17
  5. Step 5: Solve for x
    x = 160.17/13.76
  6. Step 6: Final answer
    x = 11.64

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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.