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Finding the Fourth Proportional to 85.20, 127.80 and 54.69

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Solution

The fourth proportional to 85.20, 127.80 and 54.69 is: 82.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.20 : 127.80 = 54.69 : x
  2. Step 2: Convert to fraction form
    85.20/127.80 = 54.69/x
  3. Step 3: Cross multiply
    85.20x = 127.80 × 54.69
  4. Step 4: Simplify right side
    85.20x = 6,989.38
  5. Step 5: Solve for x
    x = 6,989.38/85.20
  6. Step 6: Final answer
    x = 82.04

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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.