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Finding the Fourth Proportional to 206.75, 285.36 and 128.08

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Solution

The fourth proportional to 206.75, 285.36 and 128.08 is: 176.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.75 : 285.36 = 128.08 : x
  2. Step 2: Convert to fraction form
    206.75/285.36 = 128.08/x
  3. Step 3: Cross multiply
    206.75x = 285.36 × 128.08
  4. Step 4: Simplify right side
    206.75x = 36,548.27
  5. Step 5: Solve for x
    x = 36,548.27/206.75
  6. Step 6: Final answer
    x = 176.78

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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.