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Finding the Fourth Proportional to 206.34, 309.57 and 129.21

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Solution

The fourth proportional to 206.34, 309.57 and 129.21 is: 193.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.34 : 309.57 = 129.21 : x
  2. Step 2: Convert to fraction form
    206.34/309.57 = 129.21/x
  3. Step 3: Cross multiply
    206.34x = 309.57 × 129.21
  4. Step 4: Simplify right side
    206.34x = 39,997.99
  5. Step 5: Solve for x
    x = 39,997.99/206.34
  6. Step 6: Final answer
    x = 193.85

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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.