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Finding the Fourth Proportional to 206.84, 285.42 and 128.18

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Solution

The fourth proportional to 206.84, 285.42 and 128.18 is: 176.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.84 : 285.42 = 128.18 : x
  2. Step 2: Convert to fraction form
    206.84/285.42 = 128.18/x
  3. Step 3: Cross multiply
    206.84x = 285.42 × 128.18
  4. Step 4: Simplify right side
    206.84x = 36,585.14
  5. Step 5: Solve for x
    x = 36,585.14/206.84
  6. Step 6: Final answer
    x = 176.88

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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.