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Finding the Fourth Proportional to 391.89, 540.32 and 286.89

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Solution

The fourth proportional to 391.89, 540.32 and 286.89 is: 395.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.89 : 540.32 = 286.89 : x
  2. Step 2: Convert to fraction form
    391.89/540.32 = 286.89/x
  3. Step 3: Cross multiply
    391.89x = 540.32 × 286.89
  4. Step 4: Simplify right side
    391.89x = 155,010.97
  5. Step 5: Solve for x
    x = 155,010.97/391.89
  6. Step 6: Final answer
    x = 395.55

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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.