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Finding the Fourth Proportional to 80.87, 121.28 and 42.38

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Solution

The fourth proportional to 80.87, 121.28 and 42.38 is: 63.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.87 : 121.28 = 42.38 : x
  2. Step 2: Convert to fraction form
    80.87/121.28 = 42.38/x
  3. Step 3: Cross multiply
    80.87x = 121.28 × 42.38
  4. Step 4: Simplify right side
    80.87x = 5,139.03
  5. Step 5: Solve for x
    x = 5,139.03/80.87
  6. Step 6: Final answer
    x = 63.54

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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.