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Finding the Fourth Proportional to 85.38, 128.08 and 44.78

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Solution

The fourth proportional to 85.38, 128.08 and 44.78 is: 67.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.38 : 128.08 = 44.78 : x
  2. Step 2: Convert to fraction form
    85.38/128.08 = 44.78/x
  3. Step 3: Cross multiply
    85.38x = 128.08 × 44.78
  4. Step 4: Simplify right side
    85.38x = 5,735.20
  5. Step 5: Solve for x
    x = 5,735.20/85.38
  6. Step 6: Final answer
    x = 67.17

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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.