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Finding the Fourth Proportional to 73.62, 109.89 and 66.78

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Solution

The fourth proportional to 73.62, 109.89 and 66.78 is: 99.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    73.62 : 109.89 = 66.78 : x
  2. Step 2: Convert to fraction form
    73.62/109.89 = 66.78/x
  3. Step 3: Cross multiply
    73.62x = 109.89 × 66.78
  4. Step 4: Simplify right side
    73.62x = 7,338.45
  5. Step 5: Solve for x
    x = 7,338.45/73.62
  6. Step 6: Final answer
    x = 99.68

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.