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Finding the Fourth Proportional to 391.50, 540.40 and 251.68

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Solution

The fourth proportional to 391.50, 540.40 and 251.68 is: 347.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.50 : 540.40 = 251.68 : x
  2. Step 2: Convert to fraction form
    391.50/540.40 = 251.68/x
  3. Step 3: Cross multiply
    391.50x = 540.40 × 251.68
  4. Step 4: Simplify right side
    391.50x = 136,007.87
  5. Step 5: Solve for x
    x = 136,007.87/391.50
  6. Step 6: Final answer
    x = 347.40

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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.