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Finding the Fourth Proportional to 68.61, 102.72 and 42.85

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Solution

The fourth proportional to 68.61, 102.72 and 42.85 is: 64.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.61 : 102.72 = 42.85 : x
  2. Step 2: Convert to fraction form
    68.61/102.72 = 42.85/x
  3. Step 3: Cross multiply
    68.61x = 102.72 × 42.85
  4. Step 4: Simplify right side
    68.61x = 4,401.60
  5. Step 5: Solve for x
    x = 4,401.60/68.61
  6. Step 6: Final answer
    x = 64.15

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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.