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Finding the Fourth Proportional to 85.40, 127.89 and 54.55

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Solution

The fourth proportional to 85.40, 127.89 and 54.55 is: 81.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.40 : 127.89 = 54.55 : x
  2. Step 2: Convert to fraction form
    85.40/127.89 = 54.55/x
  3. Step 3: Cross multiply
    85.40x = 127.89 × 54.55
  4. Step 4: Simplify right side
    85.40x = 6,976.40
  5. Step 5: Solve for x
    x = 6,976.40/85.40
  6. Step 6: Final answer
    x = 81.69

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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.