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Finding the Fourth Proportional to 391.21, 539.71 and 243.89

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Solution

The fourth proportional to 391.21, 539.71 and 243.89 is: 336.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.21 : 539.71 = 243.89 : x
  2. Step 2: Convert to fraction form
    391.21/539.71 = 243.89/x
  3. Step 3: Cross multiply
    391.21x = 539.71 × 243.89
  4. Step 4: Simplify right side
    391.21x = 131,629.87
  5. Step 5: Solve for x
    x = 131,629.87/391.21
  6. Step 6: Final answer
    x = 336.47

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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.