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Finding the Fourth Proportional to 391.78, 588.21 and 209.26

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Solution

The fourth proportional to 391.78, 588.21 and 209.26 is: 314.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.78 : 588.21 = 209.26 : x
  2. Step 2: Convert to fraction form
    391.78/588.21 = 209.26/x
  3. Step 3: Cross multiply
    391.78x = 588.21 × 209.26
  4. Step 4: Simplify right side
    391.78x = 123,088.82
  5. Step 5: Solve for x
    x = 123,088.82/391.78
  6. Step 6: Final answer
    x = 314.18

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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.