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Finding the Fourth Proportional to 391.72, 587.94 and 209

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Solution

The fourth proportional to 391.72, 587.94 and 209 is: 313.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.72 : 587.94 = 209 : x
  2. Step 2: Convert to fraction form
    391.72/587.94 = 209/x
  3. Step 3: Cross multiply
    391.72x = 587.94 × 209
  4. Step 4: Simplify right side
    391.72x = 122,879.46
  5. Step 5: Solve for x
    x = 122,879.46/391.72
  6. Step 6: Final answer
    x = 313.69

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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.