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Finding the Fourth Proportional to 206.97, 310.68 and 85.31

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Solution

The fourth proportional to 206.97, 310.68 and 85.31 is: 128.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.97 : 310.68 = 85.31 : x
  2. Step 2: Convert to fraction form
    206.97/310.68 = 85.31/x
  3. Step 3: Cross multiply
    206.97x = 310.68 × 85.31
  4. Step 4: Simplify right side
    206.97x = 26,504.11
  5. Step 5: Solve for x
    x = 26,504.11/206.97
  6. Step 6: Final answer
    x = 128.06

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.