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Finding the Fourth Proportional to 77.38, 106.78 and 42.88

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Solution

The fourth proportional to 77.38, 106.78 and 42.88 is: 59.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.38 : 106.78 = 42.88 : x
  2. Step 2: Convert to fraction form
    77.38/106.78 = 42.88/x
  3. Step 3: Cross multiply
    77.38x = 106.78 × 42.88
  4. Step 4: Simplify right side
    77.38x = 4,578.73
  5. Step 5: Solve for x
    x = 4,578.73/77.38
  6. Step 6: Final answer
    x = 59.17

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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.