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Finding the Fourth Proportional to 139.72, 192.80 and 80.71

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Solution

The fourth proportional to 139.72, 192.80 and 80.71 is: 111.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.72 : 192.80 = 80.71 : x
  2. Step 2: Convert to fraction form
    139.72/192.80 = 80.71/x
  3. Step 3: Cross multiply
    139.72x = 192.80 × 80.71
  4. Step 4: Simplify right side
    139.72x = 15,560.89
  5. Step 5: Solve for x
    x = 15,560.89/139.72
  6. Step 6: Final answer
    x = 111.37

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.