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Finding the Fourth Proportional to 206.70, 285.15 and 123.78

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Solution

The fourth proportional to 206.70, 285.15 and 123.78 is: 170.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.70 : 285.15 = 123.78 : x
  2. Step 2: Convert to fraction form
    206.70/285.15 = 123.78/x
  3. Step 3: Cross multiply
    206.70x = 285.15 × 123.78
  4. Step 4: Simplify right side
    206.70x = 35,294.75
  5. Step 5: Solve for x
    x = 35,294.75/206.70
  6. Step 6: Final answer
    x = 170.75

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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.