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Finding the Fourth Proportional to 20.86, 28.78 and 18.13

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Solution

The fourth proportional to 20.86, 28.78 and 18.13 is: 25.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.86 : 28.78 = 18.13 : x
  2. Step 2: Convert to fraction form
    20.86/28.78 = 18.13/x
  3. Step 3: Cross multiply
    20.86x = 28.78 × 18.13
  4. Step 4: Simplify right side
    20.86x = 521.73
  5. Step 5: Solve for x
    x = 521.73/20.86
  6. Step 6: Final answer
    x = 25.01

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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.