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Finding the Fourth Proportional to 212.72, 319.09 and 75.78

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Solution

The fourth proportional to 212.72, 319.09 and 75.78 is: 113.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.72 : 319.09 = 75.78 : x
  2. Step 2: Convert to fraction form
    212.72/319.09 = 75.78/x
  3. Step 3: Cross multiply
    212.72x = 319.09 × 75.78
  4. Step 4: Simplify right side
    212.72x = 24,180.45
  5. Step 5: Solve for x
    x = 24,180.45/212.72
  6. Step 6: Final answer
    x = 113.68

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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.