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Finding the Fourth Proportional to 68.74, 103.11 and 20.64

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Solution

The fourth proportional to 68.74, 103.11 and 20.64 is: 30.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.74 : 103.11 = 20.64 : x
  2. Step 2: Convert to fraction form
    68.74/103.11 = 20.64/x
  3. Step 3: Cross multiply
    68.74x = 103.11 × 20.64
  4. Step 4: Simplify right side
    68.74x = 2,128.19
  5. Step 5: Solve for x
    x = 2,128.19/68.74
  6. Step 6: Final answer
    x = 30.96

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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.