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Finding the Fourth Proportional to 68.78, 103.11 and 30.21

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Solution

The fourth proportional to 68.78, 103.11 and 30.21 is: 45.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.78 : 103.11 = 30.21 : x
  2. Step 2: Convert to fraction form
    68.78/103.11 = 30.21/x
  3. Step 3: Cross multiply
    68.78x = 103.11 × 30.21
  4. Step 4: Simplify right side
    68.78x = 3,114.95
  5. Step 5: Solve for x
    x = 3,114.95/68.78
  6. Step 6: Final answer
    x = 45.29

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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.