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Finding the Fourth Proportional to 391.69, 540.40 and 251.88

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Solution

The fourth proportional to 391.69, 540.40 and 251.88 is: 347.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.69 : 540.40 = 251.88 : x
  2. Step 2: Convert to fraction form
    391.69/540.40 = 251.88/x
  3. Step 3: Cross multiply
    391.69x = 540.40 × 251.88
  4. Step 4: Simplify right side
    391.69x = 136,115.95
  5. Step 5: Solve for x
    x = 136,115.95/391.69
  6. Step 6: Final answer
    x = 347.51

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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.