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Finding the Fourth Proportional to 13.76, 20.64 and 9

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Solution

The fourth proportional to 13.76, 20.64 and 9 is: 13.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.76 : 20.64 = 9 : x
  2. Step 2: Convert to fraction form
    13.76/20.64 = 9/x
  3. Step 3: Cross multiply
    13.76x = 20.64 × 9
  4. Step 4: Simplify right side
    13.76x = 185.76
  5. Step 5: Solve for x
    x = 185.76/13.76
  6. Step 6: Final answer
    x = 13.50

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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.