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Finding the Fourth Proportional to 391.71, 587.79 and 209.22

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Solution

The fourth proportional to 391.71, 587.79 and 209.22 is: 313.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.71 : 587.79 = 209.22 : x
  2. Step 2: Convert to fraction form
    391.71/587.79 = 209.22/x
  3. Step 3: Cross multiply
    391.71x = 587.79 × 209.22
  4. Step 4: Simplify right side
    391.71x = 122,977.42
  5. Step 5: Solve for x
    x = 122,977.42/391.71
  6. Step 6: Final answer
    x = 313.95

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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.