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Finding the Fourth Proportional to 391.91, 587.86 and 208.74

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Solution

The fourth proportional to 391.91, 587.86 and 208.74 is: 313.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.91 : 587.86 = 208.74 : x
  2. Step 2: Convert to fraction form
    391.91/587.86 = 208.74/x
  3. Step 3: Cross multiply
    391.91x = 587.86 × 208.74
  4. Step 4: Simplify right side
    391.91x = 122,711.58
  5. Step 5: Solve for x
    x = 122,711.58/391.91
  6. Step 6: Final answer
    x = 313.12

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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.