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Finding the Fourth Proportional to 391.21, 539.63 and 258.43

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Solution

The fourth proportional to 391.21, 539.63 and 258.43 is: 356.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.21 : 539.63 = 258.43 : x
  2. Step 2: Convert to fraction form
    391.21/539.63 = 258.43/x
  3. Step 3: Cross multiply
    391.21x = 539.63 × 258.43
  4. Step 4: Simplify right side
    391.21x = 139,455.92
  5. Step 5: Solve for x
    x = 139,455.92/391.21
  6. Step 6: Final answer
    x = 356.48

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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.