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Finding the Fourth Proportional to 391.31, 587.31 and 208.85

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Solution

The fourth proportional to 391.31, 587.31 and 208.85 is: 313.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.31 : 587.31 = 208.85 : x
  2. Step 2: Convert to fraction form
    391.31/587.31 = 208.85/x
  3. Step 3: Cross multiply
    391.31x = 587.31 × 208.85
  4. Step 4: Simplify right side
    391.31x = 122,659.69
  5. Step 5: Solve for x
    x = 122,659.69/391.31
  6. Step 6: Final answer
    x = 313.46

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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.