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Finding the Fourth Proportional to 20.21, 30.29 and 13.79

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Solution

The fourth proportional to 20.21, 30.29 and 13.79 is: 20.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.21 : 30.29 = 13.79 : x
  2. Step 2: Convert to fraction form
    20.21/30.29 = 13.79/x
  3. Step 3: Cross multiply
    20.21x = 30.29 × 13.79
  4. Step 4: Simplify right side
    20.21x = 417.48
  5. Step 5: Solve for x
    x = 417.48/20.21
  6. Step 6: Final answer
    x = 20.66

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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.