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Finding the Fourth Proportional to 13.47, 20.21 and 8.40

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Solution

The fourth proportional to 13.47, 20.21 and 8.40 is: 12.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.47 : 20.21 = 8.40 : x
  2. Step 2: Convert to fraction form
    13.47/20.21 = 8.40/x
  3. Step 3: Cross multiply
    13.47x = 20.21 × 8.40
  4. Step 4: Simplify right side
    13.47x = 169.72
  5. Step 5: Solve for x
    x = 169.72/13.47
  6. Step 6: Final answer
    x = 12.60

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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.