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Finding the Fourth Proportional to 391.68, 540.20 and 251.81

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Solution

The fourth proportional to 391.68, 540.20 and 251.81 is: 347.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.68 : 540.20 = 251.81 : x
  2. Step 2: Convert to fraction form
    391.68/540.20 = 251.81/x
  3. Step 3: Cross multiply
    391.68x = 540.20 × 251.81
  4. Step 4: Simplify right side
    391.68x = 136,029.74
  5. Step 5: Solve for x
    x = 136,029.74/391.68
  6. Step 6: Final answer
    x = 347.30

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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.