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Finding the Fourth Proportional to 391.90, 541.20 and 281.74

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Solution

The fourth proportional to 391.90, 541.20 and 281.74 is: 389.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.90 : 541.20 = 281.74 : x
  2. Step 2: Convert to fraction form
    391.90/541.20 = 281.74/x
  3. Step 3: Cross multiply
    391.90x = 541.20 × 281.74
  4. Step 4: Simplify right side
    391.90x = 152,477.69
  5. Step 5: Solve for x
    x = 152,477.69/391.90
  6. Step 6: Final answer
    x = 389.07

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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.