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Finding the Fourth Proportional to 18.20, 25.12 and 15.80

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Solution

The fourth proportional to 18.20, 25.12 and 15.80 is: 21.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.20 : 25.12 = 15.80 : x
  2. Step 2: Convert to fraction form
    18.20/25.12 = 15.80/x
  3. Step 3: Cross multiply
    18.20x = 25.12 × 15.80
  4. Step 4: Simplify right side
    18.20x = 396.90
  5. Step 5: Solve for x
    x = 396.90/18.20
  6. Step 6: Final answer
    x = 21.81

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.