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Finding the Fourth Proportional to 391.68, 539.19 and 356.85

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Solution

The fourth proportional to 391.68, 539.19 and 356.85 is: 491.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.68 : 539.19 = 356.85 : x
  2. Step 2: Convert to fraction form
    391.68/539.19 = 356.85/x
  3. Step 3: Cross multiply
    391.68x = 539.19 × 356.85
  4. Step 4: Simplify right side
    391.68x = 192,409.95
  5. Step 5: Solve for x
    x = 192,409.95/391.68
  6. Step 6: Final answer
    x = 491.24

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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.