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Finding the Fourth Proportional to 206.80, 285.32 and 128.14

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Solution

The fourth proportional to 206.80, 285.32 and 128.14 is: 176.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.80 : 285.32 = 128.14 : x
  2. Step 2: Convert to fraction form
    206.80/285.32 = 128.14/x
  3. Step 3: Cross multiply
    206.80x = 285.32 × 128.14
  4. Step 4: Simplify right side
    206.80x = 36,560.90
  5. Step 5: Solve for x
    x = 36,560.90/206.80
  6. Step 6: Final answer
    x = 176.79

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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.