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Finding the Fourth Proportional to 213.20, 319.86 and 129.91

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Solution

The fourth proportional to 213.20, 319.86 and 129.91 is: 194.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.20 : 319.86 = 129.91 : x
  2. Step 2: Convert to fraction form
    213.20/319.86 = 129.91/x
  3. Step 3: Cross multiply
    213.20x = 319.86 × 129.91
  4. Step 4: Simplify right side
    213.20x = 41,551.41
  5. Step 5: Solve for x
    x = 41,551.41/213.20
  6. Step 6: Final answer
    x = 194.90

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.