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Finding the Fourth Proportional to 355.71, 490.89 and 215.80

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Solution

The fourth proportional to 355.71, 490.89 and 215.80 is: 297.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    355.71 : 490.89 = 215.80 : x
  2. Step 2: Convert to fraction form
    355.71/490.89 = 215.80/x
  3. Step 3: Cross multiply
    355.71x = 490.89 × 215.80
  4. Step 4: Simplify right side
    355.71x = 105,932.98
  5. Step 5: Solve for x
    x = 105,932.98/355.71
  6. Step 6: Final answer
    x = 297.81

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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.