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Finding the Fourth Proportional to 13.85, 20.76 and 5.28

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Solution

The fourth proportional to 13.85, 20.76 and 5.28 is: 7.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.85 : 20.76 = 5.28 : x
  2. Step 2: Convert to fraction form
    13.85/20.76 = 5.28/x
  3. Step 3: Cross multiply
    13.85x = 20.76 × 5.28
  4. Step 4: Simplify right side
    13.85x = 109.62
  5. Step 5: Solve for x
    x = 109.62/13.85
  6. Step 6: Final answer
    x = 7.92

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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.