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Finding the Fourth Proportional to 206.20, 284.40 and 128.50

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Solution

The fourth proportional to 206.20, 284.40 and 128.50 is: 177.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.20 : 284.40 = 128.50 : x
  2. Step 2: Convert to fraction form
    206.20/284.40 = 128.50/x
  3. Step 3: Cross multiply
    206.20x = 284.40 × 128.50
  4. Step 4: Simplify right side
    206.20x = 36,545.40
  5. Step 5: Solve for x
    x = 36,545.40/206.20
  6. Step 6: Final answer
    x = 177.23

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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.