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Finding the Fourth Proportional to 139.07, 191.88 and 80.81

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Solution

The fourth proportional to 139.07, 191.88 and 80.81 is: 111.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.07 : 191.88 = 80.81 : x
  2. Step 2: Convert to fraction form
    139.07/191.88 = 80.81/x
  3. Step 3: Cross multiply
    139.07x = 191.88 × 80.81
  4. Step 4: Simplify right side
    139.07x = 15,506.30
  5. Step 5: Solve for x
    x = 15,506.30/139.07
  6. Step 6: Final answer
    x = 111.50

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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.