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Finding the Fourth Proportional to 212.78, 319.14 and 68.54

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Solution

The fourth proportional to 212.78, 319.14 and 68.54 is: 102.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.78 : 319.14 = 68.54 : x
  2. Step 2: Convert to fraction form
    212.78/319.14 = 68.54/x
  3. Step 3: Cross multiply
    212.78x = 319.14 × 68.54
  4. Step 4: Simplify right side
    212.78x = 21,872.26
  5. Step 5: Solve for x
    x = 21,872.26/212.78
  6. Step 6: Final answer
    x = 102.79

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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.