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Finding the Fourth Proportional to 391.67, 587.16 and 209.20

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Solution

The fourth proportional to 391.67, 587.16 and 209.20 is: 313.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.67 : 587.16 = 209.20 : x
  2. Step 2: Convert to fraction form
    391.67/587.16 = 209.20/x
  3. Step 3: Cross multiply
    391.67x = 587.16 × 209.20
  4. Step 4: Simplify right side
    391.67x = 122,830.94
  5. Step 5: Solve for x
    x = 122,830.94/391.67
  6. Step 6: Final answer
    x = 313.61

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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.