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Finding the Fourth Proportional to 405.31, 559.11 and 257.80

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Solution

The fourth proportional to 405.31, 559.11 and 257.80 is: 355.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.31 : 559.11 = 257.80 : x
  2. Step 2: Convert to fraction form
    405.31/559.11 = 257.80/x
  3. Step 3: Cross multiply
    405.31x = 559.11 × 257.80
  4. Step 4: Simplify right side
    405.31x = 144,138.56
  5. Step 5: Solve for x
    x = 144,138.56/405.31
  6. Step 6: Final answer
    x = 355.63

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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.