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Finding the Fourth Proportional to 73.78, 111.05 and 69.86

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Solution

The fourth proportional to 73.78, 111.05 and 69.86 is: 105.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    73.78 : 111.05 = 69.86 : x
  2. Step 2: Convert to fraction form
    73.78/111.05 = 69.86/x
  3. Step 3: Cross multiply
    73.78x = 111.05 × 69.86
  4. Step 4: Simplify right side
    73.78x = 7,757.95
  5. Step 5: Solve for x
    x = 7,757.95/73.78
  6. Step 6: Final answer
    x = 105.15

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.