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Finding the Fourth Proportional to 391.15, 586.05 and 208.90

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Solution

The fourth proportional to 391.15, 586.05 and 208.90 is: 312.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.15 : 586.05 = 208.90 : x
  2. Step 2: Convert to fraction form
    391.15/586.05 = 208.90/x
  3. Step 3: Cross multiply
    391.15x = 586.05 × 208.90
  4. Step 4: Simplify right side
    391.15x = 122,425.85
  5. Step 5: Solve for x
    x = 122,425.85/391.15
  6. Step 6: Final answer
    x = 312.99

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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.