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Finding the Fourth Proportional to 139.10, 191.88 and 80.88

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Solution

The fourth proportional to 139.10, 191.88 and 80.88 is: 111.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.10 : 191.88 = 80.88 : x
  2. Step 2: Convert to fraction form
    139.10/191.88 = 80.88/x
  3. Step 3: Cross multiply
    139.10x = 191.88 × 80.88
  4. Step 4: Simplify right side
    139.10x = 15,519.25
  5. Step 5: Solve for x
    x = 15,519.25/139.10
  6. Step 6: Final answer
    x = 111.57

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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.