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Finding the Fourth Proportional to 391.40, 540.17 and 258.56

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Solution

The fourth proportional to 391.40, 540.17 and 258.56 is: 356.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.40 : 540.17 = 258.56 : x
  2. Step 2: Convert to fraction form
    391.40/540.17 = 258.56/x
  3. Step 3: Cross multiply
    391.40x = 540.17 × 258.56
  4. Step 4: Simplify right side
    391.40x = 139,662.36
  5. Step 5: Solve for x
    x = 139,662.36/391.40
  6. Step 6: Final answer
    x = 356.83

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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.