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Finding the Fourth Proportional to 391.61, 540.40 and 216.96

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Solution

The fourth proportional to 391.61, 540.40 and 216.96 is: 299.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.61 : 540.40 = 216.96 : x
  2. Step 2: Convert to fraction form
    391.61/540.40 = 216.96/x
  3. Step 3: Cross multiply
    391.61x = 540.40 × 216.96
  4. Step 4: Simplify right side
    391.61x = 117,244.10
  5. Step 5: Solve for x
    x = 117,244.10/391.61
  6. Step 6: Final answer
    x = 299.39

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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.