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Finding the Fourth Proportional to 206.42, 284.81 and 128.74

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Solution

The fourth proportional to 206.42, 284.81 and 128.74 is: 177.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.42 : 284.81 = 128.74 : x
  2. Step 2: Convert to fraction form
    206.42/284.81 = 128.74/x
  3. Step 3: Cross multiply
    206.42x = 284.81 × 128.74
  4. Step 4: Simplify right side
    206.42x = 36,666.44
  5. Step 5: Solve for x
    x = 36,666.44/206.42
  6. Step 6: Final answer
    x = 177.63

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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.