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Finding the Fourth Proportional to 390.87, 539.19 and 243.54

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Solution

The fourth proportional to 390.87, 539.19 and 243.54 is: 335.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.87 : 539.19 = 243.54 : x
  2. Step 2: Convert to fraction form
    390.87/539.19 = 243.54/x
  3. Step 3: Cross multiply
    390.87x = 539.19 × 243.54
  4. Step 4: Simplify right side
    390.87x = 131,314.33
  5. Step 5: Solve for x
    x = 131,314.33/390.87
  6. Step 6: Final answer
    x = 335.95

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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.