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Finding the Fourth Proportional to 85.38, 127.92 and 54.90

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Solution

The fourth proportional to 85.38, 127.92 and 54.90 is: 82.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.38 : 127.92 = 54.90 : x
  2. Step 2: Convert to fraction form
    85.38/127.92 = 54.90/x
  3. Step 3: Cross multiply
    85.38x = 127.92 × 54.90
  4. Step 4: Simplify right side
    85.38x = 7,022.81
  5. Step 5: Solve for x
    x = 7,022.81/85.38
  6. Step 6: Final answer
    x = 82.25

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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.