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Finding the Fourth Proportional to 206.09, 308.75 and 128.90

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Solution

The fourth proportional to 206.09, 308.75 and 128.90 is: 193.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.09 : 308.75 = 128.90 : x
  2. Step 2: Convert to fraction form
    206.09/308.75 = 128.90/x
  3. Step 3: Cross multiply
    206.09x = 308.75 × 128.90
  4. Step 4: Simplify right side
    206.09x = 39,796.33
  5. Step 5: Solve for x
    x = 39,796.33/206.09
  6. Step 6: Final answer
    x = 193.11

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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.