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Finding the Fourth Proportional to 206.81, 285.36 and 123.90

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Solution

The fourth proportional to 206.81, 285.36 and 123.90 is: 170.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.81 : 285.36 = 123.90 : x
  2. Step 2: Convert to fraction form
    206.81/285.36 = 123.90/x
  3. Step 3: Cross multiply
    206.81x = 285.36 × 123.90
  4. Step 4: Simplify right side
    206.81x = 35,356.10
  5. Step 5: Solve for x
    x = 35,356.10/206.81
  6. Step 6: Final answer
    x = 170.96

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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.