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Finding the Fourth Proportional to 391.91, 540.84 and 217.28

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Solution

The fourth proportional to 391.91, 540.84 and 217.28 is: 299.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.91 : 540.84 = 217.28 : x
  2. Step 2: Convert to fraction form
    391.91/540.84 = 217.28/x
  3. Step 3: Cross multiply
    391.91x = 540.84 × 217.28
  4. Step 4: Simplify right side
    391.91x = 117,515.88
  5. Step 5: Solve for x
    x = 117,515.88/391.91
  6. Step 6: Final answer
    x = 299.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.