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Finding the Fourth Proportional to 212.89, 319.46 and 139.85

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Solution

The fourth proportional to 212.89, 319.46 and 139.85 is: 209.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.89 : 319.46 = 139.85 : x
  2. Step 2: Convert to fraction form
    212.89/319.46 = 139.85/x
  3. Step 3: Cross multiply
    212.89x = 319.46 × 139.85
  4. Step 4: Simplify right side
    212.89x = 44,676.58
  5. Step 5: Solve for x
    x = 44,676.58/212.89
  6. Step 6: Final answer
    x = 209.86

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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.