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Finding the Fourth Proportional to 206.85, 285.49 and 128.25

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Solution

The fourth proportional to 206.85, 285.49 and 128.25 is: 177.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.85 : 285.49 = 128.25 : x
  2. Step 2: Convert to fraction form
    206.85/285.49 = 128.25/x
  3. Step 3: Cross multiply
    206.85x = 285.49 × 128.25
  4. Step 4: Simplify right side
    206.85x = 36,614.25
  5. Step 5: Solve for x
    x = 36,614.25/206.85
  6. Step 6: Final answer
    x = 177.01

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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.