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Finding the Fourth Proportional to 355.21, 490.15 and 203.79

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Solution

The fourth proportional to 355.21, 490.15 and 203.79 is: 281.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    355.21 : 490.15 = 203.79 : x
  2. Step 2: Convert to fraction form
    355.21/490.15 = 203.79/x
  3. Step 3: Cross multiply
    355.21x = 490.15 × 203.79
  4. Step 4: Simplify right side
    355.21x = 99,887.67
  5. Step 5: Solve for x
    x = 99,887.67/355.21
  6. Step 6: Final answer
    x = 281.21

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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.