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Finding the Fourth Proportional to 207.31, 311.14 and 85.66

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Solution

The fourth proportional to 207.31, 311.14 and 85.66 is: 128.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.31 : 311.14 = 85.66 : x
  2. Step 2: Convert to fraction form
    207.31/311.14 = 85.66/x
  3. Step 3: Cross multiply
    207.31x = 311.14 × 85.66
  4. Step 4: Simplify right side
    207.31x = 26,651.58
  5. Step 5: Solve for x
    x = 26,651.58/207.31
  6. Step 6: Final answer
    x = 128.56

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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.