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Finding the Fourth Proportional to 75.89, 104.78 and 66.78

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Solution

The fourth proportional to 75.89, 104.78 and 66.78 is: 92.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    75.89 : 104.78 = 66.78 : x
  2. Step 2: Convert to fraction form
    75.89/104.78 = 66.78/x
  3. Step 3: Cross multiply
    75.89x = 104.78 × 66.78
  4. Step 4: Simplify right side
    75.89x = 6,997.38
  5. Step 5: Solve for x
    x = 6,997.38/75.89
  6. Step 6: Final answer
    x = 92.20

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.