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Finding the Fourth Proportional to 391.86, 540.74 and 217.18

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Solution

The fourth proportional to 391.86, 540.74 and 217.18 is: 299.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.86 : 540.74 = 217.18 : x
  2. Step 2: Convert to fraction form
    391.86/540.74 = 217.18/x
  3. Step 3: Cross multiply
    391.86x = 540.74 × 217.18
  4. Step 4: Simplify right side
    391.86x = 117,437.91
  5. Step 5: Solve for x
    x = 117,437.91/391.86
  6. Step 6: Final answer
    x = 299.69

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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.