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Finding the Fourth Proportional to 139.02, 191.90 and 80.85

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Solution

The fourth proportional to 139.02, 191.90 and 80.85 is: 111.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.02 : 191.90 = 80.85 : x
  2. Step 2: Convert to fraction form
    139.02/191.90 = 80.85/x
  3. Step 3: Cross multiply
    139.02x = 191.90 × 80.85
  4. Step 4: Simplify right side
    139.02x = 15,514.71
  5. Step 5: Solve for x
    x = 15,514.71/139.02
  6. Step 6: Final answer
    x = 111.60

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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.