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Finding the Fourth Proportional to 206.12, 309.25 and 128.98

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Solution

The fourth proportional to 206.12, 309.25 and 128.98 is: 193.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.12 : 309.25 = 128.98 : x
  2. Step 2: Convert to fraction form
    206.12/309.25 = 128.98/x
  3. Step 3: Cross multiply
    206.12x = 309.25 × 128.98
  4. Step 4: Simplify right side
    206.12x = 39,885.15
  5. Step 5: Solve for x
    x = 39,885.15/206.12
  6. Step 6: Final answer
    x = 193.50

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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.