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Finding the Fourth Proportional to 69.28, 103.80 and 55

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Solution

The fourth proportional to 69.28, 103.80 and 55 is: 82.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.28 : 103.80 = 55 : x
  2. Step 2: Convert to fraction form
    69.28/103.80 = 55/x
  3. Step 3: Cross multiply
    69.28x = 103.80 × 55
  4. Step 4: Simplify right side
    69.28x = 5,709
  5. Step 5: Solve for x
    x = 5,709/69.28
  6. Step 6: Final answer
    x = 82.40

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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.