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Finding the Fourth Proportional to 90.44, 136.02 and 76.78

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Solution

The fourth proportional to 90.44, 136.02 and 76.78 is: 115.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.44 : 136.02 = 76.78 : x
  2. Step 2: Convert to fraction form
    90.44/136.02 = 76.78/x
  3. Step 3: Cross multiply
    90.44x = 136.02 × 76.78
  4. Step 4: Simplify right side
    90.44x = 10,443.62
  5. Step 5: Solve for x
    x = 10,443.62/90.44
  6. Step 6: Final answer
    x = 115.48

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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.