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Finding the Fourth Proportional to 391.77, 587.39 and 209.39

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Solution

The fourth proportional to 391.77, 587.39 and 209.39 is: 313.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.77 : 587.39 = 209.39 : x
  2. Step 2: Convert to fraction form
    391.77/587.39 = 209.39/x
  3. Step 3: Cross multiply
    391.77x = 587.39 × 209.39
  4. Step 4: Simplify right side
    391.77x = 122,989.61
  5. Step 5: Solve for x
    x = 122,989.61/391.77
  6. Step 6: Final answer
    x = 313.93

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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.