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Finding the Fourth Proportional to 206.20, 284.32 and 128.57

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Solution

The fourth proportional to 206.20, 284.32 and 128.57 is: 177.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.20 : 284.32 = 128.57 : x
  2. Step 2: Convert to fraction form
    206.20/284.32 = 128.57/x
  3. Step 3: Cross multiply
    206.20x = 284.32 × 128.57
  4. Step 4: Simplify right side
    206.20x = 36,555.02
  5. Step 5: Solve for x
    x = 36,555.02/206.20
  6. Step 6: Final answer
    x = 177.28

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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.