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Finding the Fourth Proportional to 391.74, 540.15 and 281.16

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Solution

The fourth proportional to 391.74, 540.15 and 281.16 is: 387.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.74 : 540.15 = 281.16 : x
  2. Step 2: Convert to fraction form
    391.74/540.15 = 281.16/x
  3. Step 3: Cross multiply
    391.74x = 540.15 × 281.16
  4. Step 4: Simplify right side
    391.74x = 151,868.57
  5. Step 5: Solve for x
    x = 151,868.57/391.74
  6. Step 6: Final answer
    x = 387.68

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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.