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Finding the Fourth Proportional to 34.21, 47.20 and 20.39

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Solution

The fourth proportional to 34.21, 47.20 and 20.39 is: 28.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    34.21 : 47.20 = 20.39 : x
  2. Step 2: Convert to fraction form
    34.21/47.20 = 20.39/x
  3. Step 3: Cross multiply
    34.21x = 47.20 × 20.39
  4. Step 4: Simplify right side
    34.21x = 962.50
  5. Step 5: Solve for x
    x = 962.50/34.21
  6. Step 6: Final answer
    x = 28.14

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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.