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Finding the Fourth Proportional to 391.74, 540.72 and 281.28

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Solution

The fourth proportional to 391.74, 540.72 and 281.28 is: 388.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.74 : 540.72 = 281.28 : x
  2. Step 2: Convert to fraction form
    391.74/540.72 = 281.28/x
  3. Step 3: Cross multiply
    391.74x = 540.72 × 281.28
  4. Step 4: Simplify right side
    391.74x = 152,093.72
  5. Step 5: Solve for x
    x = 152,093.72/391.74
  6. Step 6: Final answer
    x = 388.25

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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.