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Finding the Fourth Proportional to 68.72, 102.88 and 42.60

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Solution

The fourth proportional to 68.72, 102.88 and 42.60 is: 63.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.72 : 102.88 = 42.60 : x
  2. Step 2: Convert to fraction form
    68.72/102.88 = 42.60/x
  3. Step 3: Cross multiply
    68.72x = 102.88 × 42.60
  4. Step 4: Simplify right side
    68.72x = 4,382.69
  5. Step 5: Solve for x
    x = 4,382.69/68.72
  6. Step 6: Final answer
    x = 63.78

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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.