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Finding the Fourth Proportional to 13.61, 20.43 and 12.87

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Solution

The fourth proportional to 13.61, 20.43 and 12.87 is: 19.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.61 : 20.43 = 12.87 : x
  2. Step 2: Convert to fraction form
    13.61/20.43 = 12.87/x
  3. Step 3: Cross multiply
    13.61x = 20.43 × 12.87
  4. Step 4: Simplify right side
    13.61x = 262.93
  5. Step 5: Solve for x
    x = 262.93/13.61
  6. Step 6: Final answer
    x = 19.32

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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.